Consolidated Statements of Changes in Shareholders' Equity (USD $) In Millions, except Share data in Thousands, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning balance, Value at Dec. 31, 2010	$ 16,498		$ 3,472	$ 5,776	$ 7,935	$ (747)	$ 62
Beginning balance, Shares at Dec. 31, 2010			694,381
Add (Deduct):
Net income	561				532		29
Net change in other comprehensive income (loss)	173					173
Stock transactions:
In purchase acquisitions, Shares			26
In purchase acquisitions, Values	1			1
In connection with equity award, Shares			1,838
In connection with equity awards, Values	0		9	(9)
Shares repurchased in connection with equity awards, Shares			(617)
Shares repurchased in connection with equity awards, Value	(17)		(3)	(14)
In connection with dividend reinvestment plan, Shares			563
In connection with dividend reinvestment plan, Value	15		3	12
In connection with preferred stock offering	0
In connection with 401(k) plan, Shares			703
In connection with 401(k) plan, Value	19		3	16
Cash dividends declared on preferred stock	0
Cash dividends declared on common stock	(226)				(226)
Equity-based compensation expense	49			49
Other, net	(24)			(1)			(23)
Ending balance, Value at Jun. 30, 2011	17,049		3,484	5,830	8,241	(574)	68
Ending balance, Shares at Jun. 30, 2011			696,894
Beginning balance, Value at Dec. 31, 2011	17,480		3,486	5,873	8,772	(713)	62
Beginning balance, Shares at Dec. 31, 2011			697,143
Add (Deduct):
Net income	983				949		34
Net change in other comprehensive income (loss)	172					172
Stock transactions:
In purchase acquisitions, Shares			28
In purchase acquisitions, Values	1			1
In connection with equity awards, Shares			2,143
In connection with equity awards, Values	13		11	2
Shares repurchased in connection with equity awards, Shares			(534)
Shares repurchased in connection with equity awards, Value	(16)		(3)	(13)
In connection with dividend reinvestment plan, Shares			15
In connection with preferred stock offering	559	559
Cash dividends declared on preferred stock	(8)				(8)
Cash dividends declared on common stock	(280)				(280)
Equity-based compensation expense	51			51
Other, net	(29)			0	0		(29)
Ending balance, Value at Jun. 30, 2012	$ 18,926	$ 559	$ 3,494	$ 5,914	$ 9,433	$ (541)	$ 67
Ending balance, Shares at Jun. 30, 2012			698,795