Consolidated Statements of Changes in Equity (Unaudited) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	Total USD ($)	Preferred Stock [Member] USD ($)	Preferred Stock [Member] Series A Preferred Stock [Member] USD ($)	Common Shares [Member] USD ($)	Common Shares [Member] Series A Preferred Stock [Member]	Capital Surplus [Member] USD ($)	Retained Earnings [Member] USD ($)	Retained Earnings [Member] Series A Preferred Stock [Member] USD ($)	Treasury Stock, at Cost [Member] USD ($)	Treasury Stock, at Cost [Member] Series A Preferred Stock [Member] USD ($)	Accumulated Other Comprehensive Income (Loss) [Member] USD ($)	Noncontrolling Interests [Member] USD ($)
Beginning Balance at Dec. 31, 2013		$ 291		$ 1,017		$ 4,022	$ 7,606		$ (2,281)		$ (352)	$ 17
Beginning Balance, Common Shares at Dec. 31, 2013				890,724
Beginning Balance, Preferred Shares at Dec. 31, 2013		2,905
Net income (loss)	242						242
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	29										29
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	(1)										(1)
Foreign currency translation adjustments, net of income taxes	(2)										(2)
Net pension and postretirement benefit costs, net of income taxes	2										2
Deferred compensation						(4)
Cash dividends declared on common shares							(49)
Cash dividends declared on Noncumulative Series A Preferred Stock								(6)
Common shares repurchased, value									(130)
Common shares repurchased, shares				(9,845)
Common shares reissued (returned) for stock options and other employee benefit plans						(57)			76
Common shares reissued (returned) for stock options and other employee benefit plans, shares				3,990
Net contribution from (distribution to) noncontrolling interests												(1)
Ending Balance at Mar. 31, 2014	10,419	291		1,017		3,961	7,793		(2,335)		(324)	16
Ending Balance, Common Shares at Mar. 31, 2014				884,869
Ending Balance, Preferred Shares at Mar. 31, 2014		2,905
Beginning Balance at Dec. 31, 2014	10,542	291		1,017		3,986	8,273		(2,681)		(356)	12
Beginning Balance, Common Shares at Dec. 31, 2014				859,403
Beginning Balance, Preferred Shares at Dec. 31, 2014		2,905
Net income (loss)	235						233					2
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	55										55
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	32										32
Foreign currency translation adjustments, net of income taxes	(13)										(13)
Net pension and postretirement benefit costs, net of income taxes	3										3
Deferred compensation						5
Cash dividends declared on common shares							(55)
Cash dividends declared on Noncumulative Series A Preferred Stock								(6)
Common shares repurchased, value									(197)
Common shares repurchased, shares				(14,087)
Common shares exchanged for Series A Preferred Stock			(1)							1
Common shares exchanged for Series A Preferred Stock, shares			(5)		33
Common shares reissued (returned) for stock options and other employee benefit plans						(81)			97
Common shares reissued (returned) for stock options and other employee benefit plans, shares				5,571
Net contribution from (distribution to) noncontrolling interests												(4)
Ending Balance at Mar. 31, 2015	$ 10,613	$ 290		$ 1,017		$ 3,910	$ 8,445		$ (2,780)		$ (279)	$ 10
Ending Balance, Common Shares at Mar. 31, 2015				850,920
Ending Balance, Preferred Shares at Mar. 31, 2015		2,900