(Loss) Earnings per Common Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income (Numerator):
NET (LOSS) INCOME	$ (1,045)	$ 270	$ (478)	$ 544
Earnings applicable to non-vested restricted stock	0	0	0	(1)
Net (loss) income applicable to common stock for computing basic (loss) earnings per common share	(1,045)	270	(478)	543
Net (loss) income as adjusted for purposes of computing diluted (loss) earnings per common share	$ (1,045)	$ 270	$ (478)	$ 543
Weighted average number of shares:
Outstanding during period (in shares)	598,350,000	622,769,000	609,542,000	621,370,000
Non-vested restricted stock (in shares)	(3,763,000)	(2,541,000)	(3,438,000)	(2,582,000)
Non-vested restricted stock units (in shares)	0	920,000	0	960,000
Weighted average shares outstanding for computing basic (loss) earnings per common share (in shares)	594,587,000	621,148,000	606,104,000	619,748,000
Incremental common shares attributable to dilutive securities:
Shares issuable under convertible securities (in shares)	0	13,000	0	13,000
Shares issuable under incentive compensation plans (in shares)	0	2,135,000	0	2,067,000
Number of shares as adjusted for purposes of computing diluted (loss) earnings per common share (in shares)	594,587,000	623,296,000	606,104,000	621,828,000
Basic earnings per common share:
Basic (loss) earnings per common share (in dollars per share)	$ (1.76)	$ 0.43	$ (0.79)	$ 0.88
Diluted earnings per common share:
Diluted (loss) earnings per common share (in dollars per share)	$ (1.76)	$ 0.43	$ (0.79)	$ 0.87
Number of shares of common stock excluded from the computation of diluted earnings per share (in shares)	1,160,000		1,370,000
Stock option awards
Diluted earnings per common share:
Number of shares of common stock excluded from the computation of diluted earnings per share (in shares)	2,700,000	2,000,000	2,500,000	2,200,000