Reconciliation of Net Income/(Loss) to Net Income/(Loss) Available to Common Shareholders (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Net Income (Loss) Attributable to Parent	$ 377	$ 275	$ 729		$ 525
Dividends, Preferred Stock, Cash	(9)	(3)	(18)	[1]	(6)
Undistributed Earnings Allocated to Participating Securities	(3)	(2)	(6)		(4)
Net income/(loss) available to common shareholders	365	270	705		515
Average basic common shares	535,172,000	533,964,000	535,425,000		533,532,000
Stock options	2,000,000	1,000,000	2,000,000		1,000,000
Restricted stock	3,000,000	2,000,000	3,000,000		2,000,000
Average diluted common shares	539,763,000	537,495,000	539,812,000		536,951,000
Net income/(loss) per average common share - diluted	$ 0.68	$ 0.50	$ 1.31		$ 0.96
Earnings Per Share, Basic	$ 0.68	$ 0.51	$ 1.32		$ 0.97
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent			729		525
Dividends, Preferred Stock, Cash			$ (18)	[1]	$ (6)

[1] Dividends were $2,022 per share for Perpetual Preferred Stock Series A and B and $2,856 per share for Perpetual Preferred Stock Series E for the six months ended June 30, 2013.