Consolidated Statements of Changes in Equity (USD $) In Millions, except Share data in Thousands, unless otherwise specified	Total	Preferred Stock [Member]	Common Shares [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Retained Earnings [Member] Series A Preferred Stock [Member]	Treasury Stock, at Cost [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2011		$ 291	$ 1,017	$ 4,194	$ 6,246		$ (1,815)	$ (28)	$ 17
Beginning Balance, Common Shares at Dec. 31, 2011			953,008
Beginning Balance, Preferred Shares at Dec. 31, 2011		2,905
Net income (loss)	865				858				7
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	(98)							(98)
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	20							20
Foreign currency translation adjustments, net of income taxes	10							10
Net pension and postretirement benefit costs, net of income taxes	(28)							(28)
Deferred compensation				17
Cash dividends declared on common shares					(169)
Cash dividends declared on Noncumulative Series A Preferred Stock						(22)
Common shares repurchased, value							(251)
Common shares repurchased, shares			(30,637)
Common shares reissued (returned) for stock options and other employee benefit plans				(85)			114
Common shares reissued (returned) for stock options and other employee benefit plans, shares			3,398
Net contribution from (distribution to) noncontrolling interests									14
Ending Balance at Dec. 31, 2012		291	1,017	4,126	6,913		(1,952)	(124)	38
Ending Balance, Common Shares at Dec. 31, 2012			925,769
Ending Balance, Preferred Shares at Dec. 31, 2012		2,905
Net income (loss)	910				910
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	(292)							(292)
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	(29)							(29)
Foreign currency translation adjustments, net of income taxes	(13)							(13)
Net pension and postretirement benefit costs, net of income taxes	106							106
Cash dividends declared on common shares					(194)
Cash dividends declared on Noncumulative Series A Preferred Stock						(23)
Common shares repurchased, value							(474)
Common shares repurchased, shares			(41,599)
Common shares reissued (returned) for stock options and other employee benefit plans				(104)			145
Common shares reissued (returned) for stock options and other employee benefit plans, shares			6,554
Net contribution from (distribution to) noncontrolling interests									(21)
Ending Balance at Dec. 31, 2013	10,320	291	1,017	4,022	7,606		(2,281)	(352)	17
Ending Balance, Common Shares at Dec. 31, 2013			890,724
Ending Balance, Preferred Shares at Dec. 31, 2013		2,905
Net income (loss)	907				900				7
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	59							59
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	3							3
Foreign currency translation adjustments, net of income taxes	(20)							(20)
Net pension and postretirement benefit costs, net of income taxes	(46)							(46)
Deferred compensation				2
Cash dividends declared on common shares					(218)
Cash dividends declared on Noncumulative Series A Preferred Stock						(22)
Common shares repurchased, value							(484)
Common shares repurchased, shares			(36,285)
Common shares reissued (returned) for stock options and other employee benefit plans				(38)			84
Common shares reissued (returned) for stock options and other employee benefit plans, shares			4,964
LIHTC guaranteed funds put	(7)				7
Net contribution from (distribution to) noncontrolling interests									(12)
Ending Balance at Dec. 31, 2014	$ 10,542	$ 291	$ 1,017	$ 3,986	$ 8,273		$ (2,681)	$ (356)	$ 12
Ending Balance, Common Shares at Dec. 31, 2014			859,403
Ending Balance, Preferred Shares at Dec. 31, 2014		2,905