There is no difference between the two, except for readability. The second example (ids) is more explicit than the first and perhaps more readable. But, readability is a matter of taste/opinion with many different viewpoints. Here are some guidelines...
public void SampleCode()
//Use of var is encouraged when declaration needlessly clutters code
Widget widget1a = new Widget(); //No
var widget1b = new Widget(); //Yes, I know I am getting a widget.
//Use of var is encouraged when method name defines return type
//or return is type is known without further need of code inspection
Widget widget2a = GetWidget(); //OK (Verbose)
var widget2b = GetWidget(); //Yes, But...
//Danger, Will Robinson! if GetWidget returns a foo...Code review time!
//Use of var is discouraged when method offers new clue to type
//without further code inspection
Widget widget3a = Process(); //Yes, intent is clear without any further inspection.
var widget3b = Process(); //No, What does Process do?