Stock Options and Other Stock Based Compensation (Details 2) (Stock Options, USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock Options
Number of Shares
Options outstanding, Beginning balance (in shares)	4,044
Granted (in shares)	435
Exercised (in shares)	(296)
Forfeited or expired (in shares)	(448)
Options outstanding, ending balance (in shares)	3,735	4,044
Options vested or expected to vest (in shares)	3,687
Options exercisable (in shares)	2,545
Weighted Average Exercise Price (per share)
Options outstanding, Beginning balance (in dollars per share)	$ 22.20
Granted (in dollars per share)	$ 22.50
Exercised (in dollars per share)	$ 12.41
Forfeited or expired (in dollars per share)	$ 25.20
Options outstanding, Closing balance (in dollars per share)	$ 22.65	$ 22.20
Options vested or expected to vest (in dollars per share)	$ 22.65
Options exercisable (in dollars per share)	$ 22.65
Weighted Average Remaining Contractual Term (in years)
Options outstanding, Closing balance	3 years
Options vested or expected to vest	3 years
Options exercisable	2 years 1 month 6 days
Aggregate Intrinsic Value
Options outstanding, Closing balance (in dollars)	$ 14
Options vested or expected to vest (in dollars)	14
Options exercisable (in dollars)	10
Weighted average grant-date fair value of options granted (in dollars per share)	$ 10.63	$ 13.70	$ 14.60
Aggregate intrinsic value of options exercised (in dollars)	3	4	5
Aggregate cash received from options exercised (in dollars)	$ 4	$ 5	$ 5
Weighted average assumptions used to estimate the fair value of each option grant
Expected life of options	4 years 9 months	4 years 9 months	4 years 9 months
Expected stock price volatility (as a percent)	56.60%	53.20%	53.30%
Risk-free interest rate, low end of range (as a percent)	0.60%	0.80%	1.20%
Risk-free interest rate, high end of range (as a percent)	0.80%	2.10%	2.50%
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%