Stock-Based Compensation (Details 3) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Long-term performance based plans
Stock option activity
Total options outstanding, end of period (in shares)	632,100	658,700	697,100
Weighted-Average Exercise Price
Total options outstanding, end of period (in dollars per share)	$ 25.28	$ 25.30	$ 25.38
Stock options
Stock option activity
Total options outstanding, beginning of period (in shares)	8,078,413	7,795,373	7,203,101
Granted (in shares)	771,000	1,955,000	1,258,000
Exercised (in shares)	(569,073)	(1,082,280)	(105,573)
Forfeited and cancelled (in shares)	(372,040)	(589,680)	(560,155)
Total options outstanding, end of period (in shares)	7,908,300	8,078,413	7,795,373
Exercisable at end of period (in shares)	3,746,166	2,854,272	2,722,709
Weighted-Average Exercise Price
Total options outstanding, beginning of period (in dollars per share)	$ 26.30	$ 23.24	$ 24.85
Granted (in dollars per share)	$ 30.81	$ 36.01	$ 19.15
Exercised (in dollars per share)	$ 20.02	$ 23.59	$ 15.06
Forfeited and cancelled (in dollars per share)	$ 25.71	$ 23.07	$ 33.99
Total options outstanding, end of period (in dollars per share)	$ 27.21	$ 26.30	$ 23.24
Exercisable at end of period, Weighted-Average Exercise Price (in dollars per share)	$ 25.98	$ 25.02	$ 25.77
Share-based compensation additional disclosures
Options granted during period determined to be invalid		700,000
Tax benefit from stock awards exercised	$ 3	$ 5	$ 2
Aggregate intrinsic value
Aggregate intrinsic value of stock options outstanding	61
Aggregate intrinsic value of stock options exercisable	$ 32
Restricted stock units
Restricted stock unit activity
Total restricted stock units outstanding, beginning of period (in shares)	144,226	107,249	130,040
Granted (in shares)	33,333	69,950
Vested (in shares)	(16,210)	(11,225)	(13,975)
Forfeited and cancelled (in shares)	(9,666)	(21,748)	(8,816)
Total restricted stock units outstanding, end of period (in shares)	151,683	144,226	107,249
Weighted - Average Grant Date Fair Value
Total restricted stock units outstanding, beginning of period (in dollars per share)	$ 29.22	$ 27.33	$ 27.78
Granted (in dollars per share)	$ 34.22	$ 32.00
Vested (in dollars per share)	$ 32.61	$ 31.84	$ 31.84
Forfeited and cancelled (in dollars per share)	$ 25.84	$ 27.36	$ 26.70
Total restricted stock units outstanding, end of period (in dollars per share)	$ 30.18	$ 29.22	$ 27.33
Restricted Performance Units
Restricted stock unit activity
Total restricted stock units outstanding, end of period (in shares)	64,610	74,276	93,274
Weighted - Average Grant Date Fair Value
Total restricted stock units outstanding, end of period (in dollars per share)	$ 26.72	$ 26.61	$ 26.66