diff --git a/packages/block-library/src/details/edit.js b/packages/block-library/src/details/edit.js
index d9adc14f45241c..212a457ebbf2da 100644
--- a/packages/block-library/src/details/edit.js
+++ b/packages/block-library/src/details/edit.js
@@ -61,6 +61,7 @@ function DetailsEdit( { attributes, setAttributes, clientId } ) {
 			</InspectorControls>
 			<InspectorAdvancedControls>
 				<TextControl
+					__next40pxDefaultSize
 					label={ __( 'Name attribute' ) }
 					value={ name }
 					onChange={ ( newName ) =>