diff --git a/src/main/java/com/google/api/generator/engine/lexicon/Literal.java b/src/main/java/com/google/api/generator/engine/lexicon/Literal.java
index fb97f9fd0f..8ffd5ea989 100644
--- a/src/main/java/com/google/api/generator/engine/lexicon/Literal.java
+++ b/src/main/java/com/google/api/generator/engine/lexicon/Literal.java
@@ -22,13 +22,14 @@ public class Literal {
   private static final String BOOLEAN_FALSE = "false";
   private static final String NULL_VALUE = "null";
 
-  private static final Pattern INTEGER_PATTERN = Pattern.compile("^[0-9]+$");
-  private static final Pattern LONG_PATTERN = Pattern.compile("^[0-9]+[Ll]?$");
+  private static final Pattern INTEGER_PATTERN = Pattern.compile("^\\-?[0-9]+$");
+  private static final Pattern LONG_PATTERN = Pattern.compile("^\\-?[0-9]+[Ll]?$");
   private static final Pattern FLOAT_PATTERN =
-      Pattern.compile("^[0-9]+([fF]|(\\.(([0-9]+[fF])|[fF])))?$");
+      Pattern.compile("^\\-?[0-9]+([fF]|(\\.(([0-9]+[fF])|[fF])))?$");
   private static final Pattern DOUBLE_PATTERN_ONE =
-      Pattern.compile("^[0-9]+(\\.[0-9]+)?(\\.?[eE]\\-?[0-9]+)$");
-  private static final Pattern DOUBLE_PATTERN_TWO = Pattern.compile("^\\d*\\.\\d+$|^\\d+\\.\\d*$");
+      Pattern.compile("^\\-?[0-9]+(\\.[0-9]+)?(\\.?[eE]\\-?[0-9]+)$");
+  private static final Pattern DOUBLE_PATTERN_TWO =
+      Pattern.compile("^\\-?\\d*\\.\\d+$|^\\d+\\.\\d*$");
 
   public static boolean isBooleanLiteral(String str) {
     return str.equals(BOOLEAN_TRUE) || str.equals(BOOLEAN_FALSE);
diff --git a/src/test/java/com/google/api/generator/engine/lexicon/LiteralTest.java b/src/test/java/com/google/api/generator/engine/lexicon/LiteralTest.java
index ac22cbde6e..80b155045e 100644
--- a/src/test/java/com/google/api/generator/engine/lexicon/LiteralTest.java
+++ b/src/test/java/com/google/api/generator/engine/lexicon/LiteralTest.java
@@ -37,6 +37,7 @@ public void nullLDetected() {
   public void integerDetected() {
     assertThat(Literal.isIntegerLiteral("a123")).isFalse();
     assertThat(Literal.isIntegerLiteral("123")).isTrue();
+    assertThat(Literal.isIntegerLiteral("-123")).isTrue();
     assertThat(Literal.isIntegerLiteral("123L")).isFalse();
     assertThat(Literal.isIntegerLiteral("123r")).isFalse();
     assertThat(Literal.isIntegerLiteral("123e2")).isFalse();
@@ -47,6 +48,7 @@ public void longDetected() {
     assertThat(Literal.isLongLiteral("123")).isTrue();
     assertThat(Literal.isLongLiteral("123L")).isTrue();
     assertThat(Literal.isLongLiteral("123l")).isTrue();
+    assertThat(Literal.isLongLiteral("-123l")).isTrue();
     assertThat(Literal.isLongLiteral("123e")).isFalse();
   }
 
@@ -58,6 +60,7 @@ public void floatDetected() {
     assertThat(Literal.isFloatLiteral("0.01")).isFalse();
     assertThat(Literal.isFloatLiteral(".01")).isFalse();
     assertThat(Literal.isFloatLiteral("123.f")).isTrue();
+    assertThat(Literal.isFloatLiteral("-123.f")).isTrue();
     assertThat(Literal.isFloatLiteral("123.F")).isTrue();
     assertThat(Literal.isFloatLiteral("123.234F")).isTrue();
     assertThat(Literal.isFloatLiteral("123.234Fe-3")).isFalse();
@@ -69,11 +72,14 @@ public void doubleDetected() {
     assertThat(Literal.isDoubleLiteral("123")).isTrue();
     assertThat(Literal.isDoubleLiteral("0.01")).isTrue();
     assertThat(Literal.isDoubleLiteral(".01")).isTrue();
+    assertThat(Literal.isDoubleLiteral("-.01")).isTrue();
     assertThat(Literal.isDoubleLiteral("123.0")).isTrue();
+    assertThat(Literal.isDoubleLiteral("-123.0")).isTrue();
     assertThat(Literal.isDoubleLiteral("123f")).isTrue();
     assertThat(Literal.isDoubleLiteral("123E-2")).isTrue();
     assertThat(Literal.isDoubleLiteral("123.134E-2")).isTrue();
     assertThat(Literal.isDoubleLiteral("123.E-2")).isTrue();
+    assertThat(Literal.isDoubleLiteral("-123.E-2")).isTrue();
     assertThat(Literal.isDoubleLiteral("123e2")).isTrue();
     assertThat(Literal.isDoubleLiteral("123e")).isFalse();
     assertThat(Literal.isDoubleLiteral("123E-")).isFalse();