Stock-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended						6 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Restricted Stock Rights	Dec. 31, 2011 Restricted Stock Rights	Dec. 31, 2010 Restricted Stock Rights	Jul. 09, 2008 Performance shares	Dec. 31, 2012 Performance shares	Dec. 31, 2012 Stock Option Plan	Dec. 31, 2011 Stock Option Plan	Dec. 31, 2010 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award, minimum (in years)									three to five years
Expiration period of options (in years)									ten years
Aggregate common stock available for issuance under stock based awards (in shares)	39,000,000
Common stock available for issuance under stock-based awards (in shares)	51,000,000
Percentage of performance shares vested for the first four years grant date, of a key employee								20.00%
Percentage of performance shares vested on expiration of key employee employment agreement								20.00%
Restricted stock rights activity
Restricted stock rights at the beginning of the period (in shares)				17,139,000
Restricted stock rights, granted (in shares)				15,498,000			2,500,000
Restricted stock rights, vested (in shares)				(3,554,000)
Restricted stock rights, forfeited (in shares)				(3,478,000)
Restricted stock rights at the ending of the period (in shares)				25,605,000	17,139,000
Restricted stock rights, weighted-average grant date fair value information
Restricted stock rights, weighted-average grant date fair value at the beginning of the period (dollars per share)				$ 12.28
Restricted stock rights, weighted-average grant date fair value, granted (dollars per share)				$ 11.81
Restricted stock rights, weighted-average grant date fair value, vested (dollars per share)				$ 12.32
Restricted stock rights, weighted-average grant date fair value, forfeited (dollars per share)				$ 14.16
Restricted stock rights, weighted-average grant date fair value (dollars per share) ending balance				$ 12.29	$ 12.28
Stock-based compensation, unrecognized compensation				$ 112				$ 37	$ 22
Stock-based compensation, unrecognized compensation weighted-average period of recognition (in years)				1.73				1.71	1.4
Stock options, income tax benefits from exercises									20	28	36
Total fair value of shares vested				45	37	40
Stock option activity
Stock options at the beginning of the period (in shares)									53,162,000
Stock options, granted (in shares)									4,296,000
Stock options, exercised (in shares)									(4,790,000)
Stock options, forfeited (in shares)									(423,000)
Stock Options, expired (in shares)									(497,000)
Stock options at the ending of the period (in shares)									51,748,000	53,162,000
Stock options, vested and expected to vest (in shares)									50,553,000
Stock options, exercisable (in shares)									39,473,000
Stock options, weighted-average strike price at the beginning of the period (in dollars per share)									$ 11.12
Stock options, weighted-average exercise price, granted (dollars per share)									$ 10.95
Stock options, weighted-average exercise price, exercised (in dollars per share)									$ 6.91
Stock options, weighted-average exercise price, forfeited (in dollars per share)									$ 12.35
Stock options, weighted-average exercise price, expired (in dollars per share)									$ 14.86
Stock options, weighted-average strike price at the end of the period (in dollars per share)									$ 11.45	$ 11.12
Stock options, weighted-average exercise price, vested and expected to vest (in dollars per share)									$ 11.44
Stock options, weighted-average exercise price, exercisable (in dollars per share)									$ 11.36
Stock options, weighted-average remaining contractual term (in years)									6.06
Stock options, weighted-average remaining contractual term, vested and expected to vest (in years)									5.52
Stock options, weighted-average remaining contractual term, exercisable (in years)									5.35
Stock options, aggregate intrinsic value									37
Stock options, aggregate intrinsic value, vested and expected to vest									37
Stock options, aggregate intrinsic value, exercisable									37
Stock options, intrinsic value of options exercised									25	47	104
Total grant date fair value of options vested									47	57	114
Method and assumptions on valuation of stock options
Expected life (in years)									7.05	6.58	5.79
Risk free interest rate (in percent)									1.12%	1.91%	2.97%
Volatility (in percent)									40.76%	43.50%	46.20%
Expected dividend yield (in percent)									1.65%	1.34%	1.33%
Weighted-average fair value at the grant date (dollars per share)									$ 3.47	$ 4.17	$ 3.98
Expected stock price volatility, low end of range (in percent)									29.70%
Expected stock price volatility, high end of range (in percent)									42.70%
Stock-based compensation, capitalized software development costs, activity
Stock-based compensation, software development at the beginning of the period	10	20	54
Stock-based compensation expense capitalized during the period	27	27	63
Amortization of capitalized stock-based compensation expense	(18)	(37)	(97)
Stock-based compensation, software development at the ending of the period	$ 19	$ 10	$ 20
Vesting period of award (in years)				three to five years