Stockholder's Equity (Details 1) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Changes in Stockholders' Equity
Beginning Balance					$ 18,285,000,000		$ 16,909,000,000
Net Income After Dividends on Preferred and Preference Stock	976,000,000	[1]	916,000,000	[1]	1,967,000,000	[1]	1,942,000,000	[1]
Other comprehensive income (loss)	0		(19,000,000)		(1,000,000)		(11,000,000)
Stock issued					479,000,000		692,000,000
Stock Repurchased During Period, Shares	2,600
Stock Repurchased During Period, Value	(117,000,000)				(117,000,000)
Cash dividends on common stock					(1,267,000,000)		(1,193,000,000)
Other					0		1,000,000
Ending Balance	19,346,000,000		18,340,000,000		19,346,000,000		18,340,000,000
Number of Common shares Issued [Member]
Changes in Stockholders' Equity
Beginning Balance, Shares					(865,664)		(843,814)
Stock issued, shares					11,586		18,634
Stock Repurchased During Period, Shares					0
Ending Balance, Shares	877,250		862,448		877,250		862,448
Number of Common shares Treasury [Member]
Changes in Stockholders' Equity
Beginning Balance, Shares					(539)		(474)
Stock Repurchased During Period, Shares					2,567
Other Share					38		45
Ending Balance, Shares	3,144		519		3,144		519
Common Stockholders' Equity [Member]
Changes in Stockholders' Equity
Beginning Balance					17,578,000,000		16,202,000,000
Net Income After Dividends on Preferred and Preference Stock					1,967,000,000		1,942,000,000
Other comprehensive income (loss)					(1,000,000)		(11,000,000)
Stock issued					479,000,000		692,000,000
Stock Repurchased During Period, Value					(117,000,000)
Cash dividends on common stock					(1,267,000,000)		(1,193,000,000)
Other					0		1,000,000
Ending Balance	18,639,000,000		17,633,000,000		18,639,000,000		17,633,000,000
Preferred and Preference Stock of Subsidiaries [Member]
Changes in Stockholders' Equity
Beginning Balance					707,000,000		707,000,000
Net Income After Dividends on Preferred and Preference Stock					0		0
Other comprehensive income (loss)					0		0
Stock issued					0		0
Stock Repurchased During Period, Value					0
Cash dividends on common stock					0		0
Other					0		0
Ending Balance	$ 707,000,000		$ 707,000,000		$ 707,000,000		$ 707,000,000

[1] After dividends on preferred and preference stock of subsidiaries