Total Equity and Other Comprehensive Income (Rollforward of Total Equity) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2013
Common Stock [Abstract]
Common Stock, Beginning Balance			$ 2,705,000,000
Capital surplus - Preferred Stock, Beginning Balance			3,946,000,000
Capital surplus - Common Stock, Beginning Balance			12,627,000,000
Retained Earnings, Beginning Balance			26,200,000,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance			503,000,000
Treasury Stock, Beginning Balance			1,430,000,000
Noncontrolling interests, Beginning Balance			1,523,000,000
Total Equity, Beginning Balance			46,074,000,000	$ 44,037,000,000
Net income	$ 1,044,000,000	$ 1,052,000,000	2,048,000,000	2,112,000,000
Other comprehensive income (loss), net of tax	(324,000,000)	225,000,000	(124,000,000)	445,000,000
Cash dividends declared [Abstract]
Common			(516,000,000)	(491,000,000)
Preferred			(115,000,000)	(115,000,000)
Common stock activity			37,000,000	60,000,000
Treasury stock activity			(887,000,000)	(165,000,000)
Other			(105,000,000)	(92,000,000)
Common Stock, Ending Balance	2,708,000,000		2,708,000,000
Capital surplus - Preferred Stock, Ending Balance	3,449,000,000		3,449,000,000
Capital surplus - Common Stock, Ending Balance	12,632,000,000		12,632,000,000
Retained Earnings, Ending Balance	27,609,000,000		27,609,000,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	379,000,000		379,000,000
Treasury Stock, Ending Balance	2,262,000,000		2,262,000,000
Noncontrolling interests, Ending Balance	1,397,000,000		1,397,000,000
Total Equity, Ending Balance	$ 45,912,000,000	$ 45,793,000,000	$ 45,912,000,000	45,793,000,000
Series K Preferred Stock [Member]
Cash dividends declared [Abstract]
Preferred stock redemption, shares	50,000		50,000
Preferred stock redemption, value	$ (500,000,000)		$ (500,000,000)
Depositary shares [Member]
Cash dividends declared [Abstract]
Preferred stock redemption, shares	500,000		500,000
Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Total Equity, Beginning Balance				$ 44,039,000,000
Cash dividends declared [Abstract]
Cumulative effect adjustment					$ 2,000,000
Common Stock [Member]
Common Stock [Abstract]
Beginning Balance (in shares)			523,000,000	533,000,000
Common stock activity, shares			1,000,000	1,000,000
Treasury stock activity, shares			(8,000,000)	(2,000,000)
Ending Balance, (in shares)	516,000,000	532,000,000	516,000,000	532,000,000
Common Stock, Beginning Balance			$ 2,705,000,000	$ 2,698,000,000
Cash dividends declared [Abstract]
Common stock activity			3,000,000	5,000,000
Common Stock, Ending Balance	$ 2,708,000,000	$ 2,703,000,000	$ 2,708,000,000	$ 2,703,000,000
Common Stock Per Share Dividends Declared			$ 0.99	$ 0.92
Common Stock [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Beginning Balance (in shares)				533,000,000
Common Stock, Beginning Balance				$ 2,698,000,000
Preferred Stock Including Additional Paid in Capital [Member]
Common Stock [Abstract]
Capital surplus - Preferred Stock, Beginning Balance			$ 3,946,000,000	3,941,000,000
Cash dividends declared [Abstract]
Preferred stock discount accretion			3,000,000	3,000,000
Capital surplus - Preferred Stock, Ending Balance	3,449,000,000	3,944,000,000	3,449,000,000	3,944,000,000
Preferred Stock Including Additional Paid in Capital [Member] | Series K Preferred Stock [Member]
Cash dividends declared [Abstract]
Preferred stock redemption, value	(500,000,000)		(500,000,000)
Preferred Stock Including Additional Paid in Capital [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Capital surplus - Preferred Stock, Beginning Balance				3,941,000,000
Common Stock Including Additional Paid in Capital [Member]
Common Stock [Abstract]
Capital surplus - Common Stock, Beginning Balance			12,627,000,000	12,416,000,000
Cash dividends declared [Abstract]
Common stock activity			34,000,000	55,000,000
Treasury stock activity			(55,000,000)	11,000,000
Other			26,000,000	24,000,000
Capital surplus - Common Stock, Ending Balance	12,632,000,000	12,506,000,000	12,632,000,000	12,506,000,000
Common Stock Including Additional Paid in Capital [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Capital surplus - Common Stock, Beginning Balance				12,416,000,000
Retained Earnings [Member]
Common Stock [Abstract]
Retained Earnings, Beginning Balance			26,200,000,000	23,251,000,000
Net income			2,043,000,000	2,111,000,000
Cash dividends declared [Abstract]
Common			(516,000,000)	(491,000,000)
Preferred			(115,000,000)	(115,000,000)
Preferred stock discount accretion			(3,000,000)	(3,000,000)
Retained Earnings, Ending Balance	27,609,000,000	24,755,000,000	27,609,000,000	24,755,000,000
Retained Earnings [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Retained Earnings, Beginning Balance				23,253,000,000
Cash dividends declared [Abstract]
Cumulative effect adjustment					$ 2,000,000
Accumulated Other Comprehensive Income (Loss) [Member]
Common Stock [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance			503,000,000	436,000,000
Other comprehensive income (loss), net of tax			(124,000,000)	445,000,000
Cash dividends declared [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	379,000,000	881,000,000	379,000,000	881,000,000
Accumulated Other Comprehensive Income (Loss) [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance				436,000,000
Treasury Stock [Member]
Common Stock [Abstract]
Treasury Stock, Beginning Balance			(1,430,000,000)	(408,000,000)
Cash dividends declared [Abstract]
Treasury stock activity			(832,000,000)	(176,000,000)
Treasury Stock, Ending Balance	(2,262,000,000)	(584,000,000)	(2,262,000,000)	(584,000,000)
Treasury Stock [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Treasury Stock, Beginning Balance				(408,000,000)
Noncontrolling Interest [Member]
Common Stock [Abstract]
Noncontrolling interests, Beginning Balance			1,523,000,000	1,703,000,000
Net income			5,000,000	1,000,000
Cash dividends declared [Abstract]
Other			(131,000,000)	(116,000,000)
Noncontrolling interests, Ending Balance	$ 1,397,000,000	$ 1,588,000,000	$ 1,397,000,000	1,588,000,000
Noncontrolling Interest [Member] | Cumulative effect of adopting ASC 860-50 [Member]
Common Stock [Abstract]
Noncontrolling interests, Beginning Balance				$ 1,703,000,000