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]	AOCI [Member]	Noncontrolling Interests [Member]
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 OCI	172					172
Stock transactions:
In purchase acquisitions, Shares			28
In purchase acquisitions, Values	1			1
In connection with equity award, Shares, net of repurchases			2,158
In connection with equity awards, Values, net of repurchases	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 preferred stock offerings	559	559
Cash dividends declared on common stock	(280)				(280)
Cash dividends declared on preferred stock	(8)				(8)
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
Beginning balance, Value at Dec. 31, 2012	21,223	2,116	3,499	5,973	10,129	(559)	65
Beginning balance, Shares at Dec. 31, 2012			699,728
Add (Deduct):
Net income	832				800		32
Net change in OCI	(225)					(225)
Stock transactions:
In connection with equity awards, Shares			3,462
In connection with equity awards, Values	29		17	12
Shares repurchased in connection with equity awards, Shares			(754)
Shares repurchased in connection with equity awards, Value	(23)		(4)	(19)
In connection with dividend reinvestment plan, Shares			229
In connection with dividend reinvestment plan, Value	7		1	6
In connection with 401(k) plan, Shares			330
In connection with 401(k) plan, Value	11		2	9
In connection with preferred stock offerings	487	487
Cash dividends declared on common stock	(322)				(322)
Cash dividends declared on preferred stock	(43)				(43)
Equity-based compensation expense	60			60
Other, net	(40)			1			(41)
Ending balance, Value at Jun. 30, 2013	$ 21,996	$ 2,603	$ 3,515	$ 6,042	$ 10,564	$ (784)	$ 56
Ending balance, Shares at Jun. 30, 2013			702,995