Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income (numerator):
Net income (loss) - basic and diluted	$ (33)	$ 269	$ 218	$ 471
Weighted average shares (denominator):
Weighted average shares - basic	135	134	134	134
Dilution effect of stock options and unvested restricted stock and restricted stock units outstanding at end of period	0	1	1	1
Weighted average shares - diluted	135	135	135	135
Basic --
Earnings (Loss) Per Share, Basic	$ (0.24)	$ 2.00	$ 1.62	$ 3.52
Diluted --
Earnings (Loss) Per Share, Diluted	$ (0.24)	$ 1.99	$ 1.61	$ 3.49
Earnings Per Share (Textuals) [Abstract]
Incremental shares attributable to the assumed exercise of outstanding stock options and the assumed vesting of unvested restricted stock and restricted stock units	0.6	1.0	3.0	1.0