Stock-Based Incentive Compensation Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee service share-based compensation, aggregate disclosures [Abstract]
Compensation expense	$ 31	$ 22	$ 16
Recognized tax benefit	11	8	6
Unrecognized stock-based incentive compensation expense	36	28	24
Executive long term incentive awards, aggregate disclosures [Abstract]
Vesting period (in years)	3	3	3
Stock options [Member]
Employee service share-based compensation, aggregate disclosures [Abstract]
Compensation expense	8	8	5
Unrecognized stock-based incentive compensation expense	6	6	4
Weighted average period (in years)	1.8	1.7	1.8
Executive long term incentive awards, aggregate disclosures [Abstract]
Percentage of total awards granted during the year for participating executive officers	35.00%	33.00%	34.00%
Options granted for certain of our executive officers (in shares)	903,502	459,093	301,524
Assumptions used for stock-based incentive compensation plans [Abstract]
Dividend yield	1.90%	1.20%	1.30%
Expected volatility	42.00%	48.50%	72.50%
Risk-free interest rate, minimum	0.90%	1.40%	2.70%
Risk-free interest rate, maximum	1.20%	2.90%	3.30%
Expected life (in years)	5.8	6.7	6.3
Weighted-average fair value per option granted (in dollars per share)	$ 8.35	$ 13.88	$ 16.91
Stock Options With Performance Conditions [Member]
Summary of activity for stock options [Roll Forward]
Outstanding as of beginning of year (in shares)	1,849,448
Granted - original (in shares)	99,113
Exercised (includes shares tendered) (in shares)	(1,298)
Forfeited or expired (in shares)	(679,668)
Outstanding as of end of year (in shares)	1,267,595	1,849,448
Vested or expected to vest as of end of year (in shares)	1,245,410
Exercisable as of end of year (in shares)	1,156,671
Summary of activity for stock options, additional disclosures [Abstract]
Weighted average exercise price as of beginning of year (in dollars per share)	$ 48.19
Weighted average exercise price granted - original (in dollars per share)	$ 27.26
Weighted average exercise price exercised (includes shares tendered) (in dollars per share)	$ 16.24
Weighted average exercise price forfeited or expired (in dollars per share)	$ 51.16
Weighted average exercise price outstanding as of end of year (in dollars per share)	$ 45.29	$ 48.19
Weighted average exercise price vested or expected to vest as of end of year (in dollars per share)	$ 45.60
Weighted average exercise price exercisable as of end of year (in dollars per share)	$ 46.93
Weighted average remaining contractual term outstanding as of end of year (in years)	4.15
Weighted average remaining contractual term vested or expected to vest as of end of year (in years)	4.16
Weighted average remaining contractual term exercisable as of end of year (in years)	4.19
Aggregate intrinsic value outstanding as of end of year	1
Aggregate intrinsic value vested or expected to vest as of end of year	1
Aggregate intrinsic value exercisable as of end of year	1
Total intrinsic value of options exercised	0	0	0
Total fair value of options vested	1	2	9
Stock Options With Service Conditions [Member]
Summary of activity for stock options [Roll Forward]
Outstanding as of beginning of year (in shares)	6,650,558
Granted - original (in shares)	954,642
Exercised (includes shares tendered) (in shares)	(22,798)
Forfeited or expired (in shares)	(2,066,641)
Outstanding as of end of year (in shares)	5,515,761	6,650,558
Vested or expected to vest as of end of year (in shares)	5,273,417
Exercisable as of end of year (in shares)	4,304,041
Summary of activity for stock options, additional disclosures [Abstract]
Weighted average exercise price as of beginning of year (in dollars per share)	$ 46.73
Weighted average exercise price granted - original (in dollars per share)	$ 24.75
Weighted average exercise price exercised (includes shares tendered) (in dollars per share)	$ 16.01
Weighted average exercise price forfeited or expired (in dollars per share)	$ 51.69
Weighted average exercise price outstanding as of end of year (in dollars per share)	$ 41.20	$ 46.73
Weighted average exercise price vested or expected to vest as of end of year (in dollars per share)	$ 41.89
Weighted average exercise price exercisable as of end of year (in dollars per share)	$ 45.46
Weighted average remaining contractual term outstanding as of end of year (in years)	4.07
Weighted average remaining contractual term vested or expected to vest as of end of year (in years)	3.85
Weighted average remaining contractual term exercisable as of end of year (in years)	2.72
Aggregate intrinsic value outstanding as of end of year	5
Aggregate intrinsic value vested or expected to vest as of end of year	5
Aggregate intrinsic value exercisable as of end of year	4
Total intrinsic value of options exercised	0	0	0
Total fair value of options vested	4	7	4
Performance Shares [Member]
Employee service share-based compensation, aggregate disclosures [Abstract]
Compensation expense	5	2	(1)
Unrecognized stock-based incentive compensation expense	9	4	0
Weighted average period (in years)	1.6	2.0	0
Executive long term incentive awards, aggregate disclosures [Abstract]
Percentage of total awards granted during the year for participating executive officers	36.00%	33.00%
Percentage of target award opportunities, minimum	0.00%
Percentage of target award opportunities, maximum	200.00%
Restricted stock units granted for certain of our executive officers (in shares)	306,456	215,137
Summary of activity for performance shares [Roll Forward]
Performance shares as of beginning of year (in shares)	197,449
Granted (in shares)	306,456
Forfeited (in shares)	(24,407)
Performance shares as of end of year (in shares)	479,498	197,449
Performance shares, additional disclosures [Abstract]
Weighted-average grant date fair value, outstanding as of beginning of year (in dollars per share)	$ 31.02
Weighted-average grant date fair value, granted (in dollars per share)	$ 30.07
Weighted-average grant date fair value, forfeited (in dollars per share)	$ 33.29
Weighted-average grant date fair value, outstanding as of end of year (in dollars per share)	$ 32.48	$ 31.02
Stock Appreciation Rights [Member]
Employee service share-based compensation, aggregate disclosures [Abstract]
Compensation expense	1	0	0
Unrecognized stock-based incentive compensation expense	1	1	1
Weighted average period (in years)	3.3	3.4	3.7
Stock appreciation rights [Abstract]
SARs liability	1	1
Payment for SARs exercised	0	0	0
Assumptions used for stock-based incentive compensation plans [Abstract]
Dividend yield	1.40%	1.90%	2.40%
Expected volatility	40.70%	39.10%	38.20%
Risk-free interest rate	1.30%	2.20%	1.80%
Expected life (in years)	5.0	5.0	5.0
Summary of activity for stock options [Roll Forward]
Outstanding as of beginning of year (in shares)	671,325
Granted - original (in shares)	80,225
Exercised (includes shares tendered) (in shares)	(11,875)
Forfeited or expired (in shares)	(169,994)
Outstanding as of end of year (in shares)	569,681	671,325
Vested or expected to vest as of end of year (in shares)	549,971
Exercisable as of end of year (in shares)	405,876
Summary of activity for stock options, additional disclosures [Abstract]
Weighted average exercise price as of beginning of year (in dollars per share)	$ 43.26
Weighted average exercise price granted - original (in dollars per share)	$ 27.29
Weighted average exercise price exercised (includes shares tendered) (in dollars per share)	$ 16.24
Weighted average exercise price forfeited or expired (in dollars per share)	$ 64.98
Weighted average exercise price outstanding as of end of year (in dollars per share)	$ 35.01	$ 43.26
Weighted average exercise price vested or expected to vest as of end of year (in dollars per share)	$ 35.32
Weighted average exercise price exercisable as of end of year (in dollars per share)	$ 38.01
Weighted average remaining contractual term outstanding as of end of year (in years)	1.79
Weighted average remaining contractual term vested or expected to vest as of end of year (in years)	1.74
Weighted average remaining contractual term exercisable as of end of year (in years)	1.19
Aggregate intrinsic value outstanding as of end of year	1
Aggregate intrinsic value vested or expected to vest as of end of year	1
Aggregate intrinsic value exercisable as of end of year	1
Performance shares, additional disclosures [Abstract]
Weighted-average grant date fair value, granted (in dollars per share)	$ 8.91	$ 9.41	$ 7.81
Restricted Stock Units And Awards [Member]
Employee service share-based compensation, aggregate disclosures [Abstract]
Compensation expense	17	12	12
Unrecognized stock-based incentive compensation expense	$ 20	$ 17	$ 19
Weighted average period (in years)	1.3	1.7	1.9
Restricted Stock Units [Member]
Executive long term incentive awards, aggregate disclosures [Abstract]
Percentage of total awards granted during the year for participating executive officers	29.00%	34.00%	66.00%
Restricted stock units granted for certain of our executive officers (in shares)	766,217	221,813	575,353
Summary of activity for restricted stock units [Roll Forward]
Outstanding as of beginning of year (in shares)	1,779,353
Granted (in shares)	766,217
Vested (in shares)	(653,848)
Forfeited (in shares)	(175,315)
Outstanding as of end of year (in shares)	1,716,407	1,779,353
Restricted stock units, additional disclosures [Abstract]
Weighted-average grant date fair value, RSU, outstanding as of beginning of period (in dollars per share)	$ 23.94
Weighted-average grant date fair value, granted (in dollars per share)	$ 25.08
Weighted-average grant date fair value, vested (in dollars per share)	$ 18.29
Weighted-average grant date fair value, forfeited (in dollars per share)	$ 26.20
Weighted-average grant date fair value, outstanding as of end of year (in dollars per share)	$ 26.49	$ 23.94