Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net Income	$ 570	$ 547
OCI, net of tax:
Change in unrecognized net pension and postretirement costs	11	9
Change in unrealized net gains (losses) on cash flow hedges	(115)	(54)
Change in unrealized net gains (losses) on AFS securities	197	57
Net change in FDIC's share of unrealized gains/losses on AFS securities	15	10
Other, net	3	(4)
Total OCI	111	18
Total comprehensive income	681	565
Income Tax Effect of Items Included in OCI:
Change in unrecognized net pension and postretirement costs	7	6
Change in unrealized net gains (losses) on cash flow hedges	(68)	(32)
Change in unrealized net gains (losses) on AFS securities	118	34
Net change in FDIC's share of unrealized gains/losses on AFS securities	8	5
Other, net	$ 0	$ 0