Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Assets
Card Member receivables, reserves	$ 145	$ 110
Card Member loans, reserves	$ 5	$ 5
Shareholder's Equity
Common stock, par value	$ 0.1	$ 0.1
Common stock, authorized	3.0	3.0
Common stock, issued	1.5	1.5
Common stock, outstanding	1.5	1.5
Accumulated other comprehensive loss:
Foreign currency translation adjustments, tax	$ 17	$ 329