Reconciliation of Net Income/(Loss) to Net Income/(Loss) Available to Common Shareholders (Detail) - Equity Component [Domain] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Net Income (Loss) Attributable to Parent	$ 483	$ 399	$ 912		$ 804
Dividends, Preferred Stock, Cash	(15)	(9)	(32)	[1]	(19)	[1]
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	1	3	3		5
Net Income (Loss) Available to Common Stockholders, Basic	$ 467	$ 387	$ 877		$ 780
Average basic common shares	516,968	529,764	518,983		530,459
Stock options	1,000	1,000	2,000		2,000
Restricted stock	4,000	4,000	4,000		4,000
Weighted Average Number of Shares Outstanding, Diluted	522,479	535,486	524,646		536,234
Net income/(loss) per average common share - diluted	$ 0.89	$ 0.72	$ 1.67		$ 1.45
Earnings Per Share, Basic	$ 0.90	$ 0.73	$ 1.69		$ 1.47

[1] For the six months ended June 30, 2015, dividends were $2,022 per share for both Perpetual Preferred Stock Series A and B, $2,938 per share for Perpetual Preferred Stock Series E, and $3,406 per share for Perpetual Preferred Stock Series F.For the six months ended June 30, 2014, dividends were $2,022 per share for both Perpetual Preferred Stock Series A and B, and $2,938 per share for Perpetual Preferred Stock Series E.