diff --git a/src/hwpx/oxml/document.py b/src/hwpx/oxml/document.py
index d9544b2..540d1a3 100644
--- a/src/hwpx/oxml/document.py
+++ b/src/hwpx/oxml/document.py
@@ -109,17 +109,17 @@ def _serialize_xml(element: ET.Element) -> bytes:
 
 def _paragraph_id() -> str:
     """Generate an identifier for a new paragraph element."""
-    return str(uuid4().int & 0xFFFFFFFF)
+    return str(uuid4().int & 0x7FFFFFFF)
 
 
 def _object_id() -> str:
     """Generate an identifier suitable for table and shape objects."""
-    return str(uuid4().int & 0xFFFFFFFF)
+    return str(uuid4().int & 0x7FFFFFFF)
 
 
 def _memo_id() -> str:
     """Generate a lightweight identifier for memo elements."""
-    return str(uuid4().int & 0xFFFFFFFF)
+    return str(uuid4().int & 0x7FFFFFFF)
 
 
 def _refresh_copied_paragraph_subtree_ids(paragraph: ET.Element) -> None:
diff --git a/tests/test_id_generator_range.py b/tests/test_id_generator_range.py
new file mode 100644
index 0000000..6407608
--- /dev/null
+++ b/tests/test_id_generator_range.py
@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from hwpx.oxml.document import _memo_id, _object_id, _paragraph_id
+
+
+_GENERATORS = (_paragraph_id, _object_id, _memo_id)
+
+
+def test_id_generators_stay_within_signed_int32() -> None:
+    """Generated IDs must fit in signed int32 so downstream consumers that
+    parse the ``id`` attribute as ``int`` see a non-negative value."""
+
+    for gen in _GENERATORS:
+        for _ in range(200):
+            value = int(gen())
+            assert 0 <= value < 2**31, (
+                f"{gen.__name__} produced {value} (0x{value:x}); "
+                "must be in [0, 2^31)"
+            )
+
+
+def test_id_generators_use_full_31_bit_range() -> None:
+    """The generators should still draw from a wide range so collisions
+    remain negligible. Sample 4_000 values and require at least one above
+    2^30 to guard against accidental over-restriction."""
+
+    for gen in _GENERATORS:
+        samples = [int(gen()) for _ in range(4000)]
+        assert max(samples) >= 2**30, (
+            f"{gen.__name__} samples capped at {max(samples):#x}; "
+            "expected the full [0, 2^31) range"
+        )