Idioms and Phrases with same difference
No difference at all, the same thing, as in She's my sister, or stepsister—same difference. This jocular colloquial phrase dates from about 1940.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.