Reconciliation of Net Income/(Loss) to Net Income/(Loss) Available to Common Shareholders (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net Income (Loss) Attributable to Parent	$ 447	$ 429
Dividends, Preferred Stock, Cash	(17)	(17)	[1]
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	0	(1)
Net Income (Loss) Available to Common Stockholders, Basic	$ 430	$ 411
Average basic common shares	505	521
Stock options	2	2
Restricted stock	3	4
Weighted Average Number of Shares Outstanding, Diluted	510	527
Net income/(loss) per average common share - diluted	$ 0.84	$ 0.78
Earnings Per Share, Basic	$ 0.85	$ 0.79

[1] For the three months ended March 31, 2016, dividends were $1,011 per share for both Perpetual Preferred Stock Series A and B, $1,469 per share for Perpetual Preferred Stock Series E, and $1,406 per share for Perpetual Preferred Stock Series F.For the three months ended March 31, 2015, dividends were $1,000 per share for both Perpetual Preferred Stock Series A and B, $1,469 per share for Perpetual Preferred Stock Series E, and $1,406 per share for Perpetual Preferred Stock Series F.