Share - Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent Of Share Based Award Available For Grant Limit On Increase	3.00%
Number of unused share-based awards carried forward	96,000,000
RSU performance period, minimum	1 year
RSU performance period, maximum	3 years
RSU restriction period, minimum	1 year
RSU restriction period, maximum	3 years
Long Term Incentive Plans [Member]
Compensation cost for RSU-stock [Abstract]
Tax benefit from compensation expense	$ 3	$ 0	$ 0
Other Share-Based Awards [Abstract]
Compensation cost, net of taxes	(9)	6	11
LTIP 2008 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent Of Share Based Award Available For Grant In Succeeding Calendar Year	2.00%
Restricted Stock Units (RSUs) [Member]
Stock activity rollforward
Outstanding, beginning of year (in shares)	72,400,000
Granted (in shares)	8,600,000
Vested (in shares)	(44,400,000)
Forfeited (in shares)	(500,000)
Outstanding, end of year (in shares)	36,100,000	72,400,000
RSU-stock expected to vest (in shares)	35,500,000
Outstanding, beginning of year (weighted-average grant-date fair value)	$ 3.96
Granted (weighted-average grant-date fair value)	$ 14.47
Vested (weighted-average grant-date fair value)	$ 3.19
Forfeited (weighted-average grant-date fair value)	$ 11.03
Outstanding, end of year (weighted-average grant-date fair value)	$ 7.31	$ 3.96
Outstanding, end of year (Aggregate Intrinsic Value)	388.4
RSU-stock expected to vest (Aggregate Intrinsic Value)	381.9
Fair Value Disclosures [Abstract]
Granted	123	130	171
Weighted average for multiple grant dates (per unit)	14.47	12.69	2.13
Vested	141	112	66
Intrinsic Value [Abstract]
Vested	478	522	95
Compensation cost for RSU-stock [Abstract]
Compensation cost, net of taxes	84	138	117
Tax benefit from compensation expense	49	0	0
Unrealized compensation cost on non-vested stock	49
Unrealized compensation weighted average period non-vested stock	1.3
Intrinsic Value of Stock Options [Abstract]
Compensation cost, net of taxes	84	138	117
Unrealized compensation cost on non-vested stock	49
Unrealized compensation weighted average period non-vested stock	1.3
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options expiration period, from date of grant	10 years
Stock options vesting term	3 years
Compensation cost for RSU-stock [Abstract]
Compensation cost, net of taxes	30	34	29
Tax benefit from compensation expense	17	0	0
Unrealized compensation cost on non-vested stock	13
Unrealized compensation weighted average period non-vested stock	1.3
Stock Option Activity [Abstract]
Outstanding, beginning of year (in shares)	172,500,000	225,400,000	226,200,000
Granted (in shares)	4,400,000	6,700,000	26,500,000
Exercised (in shares)	(8,200,000)	(36,500,000)	(1,300,000)
Forfeited (including expirations) (in shares)	(24,300,000)	(23,100,000)	(26,000,000)
Outstanding, end of year (in shares)	144,400,000	172,500,000	225,400,000
Exerciseable, end of year (in shares)	126,800,000	143,700,000	185,000,000
Outstanding, beginning of year (weighted-average exercise price)	$ 13.07	$ 13.36	$ 16.37
Granted (weighted-average exercise price)	$ 14.76	$ 12.75	$ 2.06
Exercised (weighted-average exercise price)	$ 9.25	$ 8.41	$ 7.35
Forfeited (including expirations) (weighted-average exercise price)	$ 29.18	$ 23.18	$ 28.28
Outstanding, end of year (weighted-average exercise price)	$ 10.63	$ 13.07	$ 13.36
Exerciseable, end of year (weighted-average exercise price)	$ 11.00	$ 14.63	$ 15.47
Stock option plans, exercise price, lower range range	$ 1.96	$ 1.96	$ 5.49
Stock option plans, exercise price, upper range	$ 16.91	$ 16.91	$ 7.83
Fair Value [Abstract]
Vested (fair value)	36	37	41
Vested (in shares)	126,800,000
Vested, with a weighted average exercise price (dollars per share)	11.00
Average remaining term	P3Y
Expected to vest	17,200,000
Weighted average exercise price (with forfeitures)	7.96
Remaining term, after forfeitures	8.0
Intrinsic Value of Stock Options [Abstract]
Intrinsic value of vested options	257	623	132
Intrinsic value of nonvested options	74	324	246
Cash received from exercise of stock options	76
New stock issuances to settle exercised options	73
Difference between fair value and shares issued	54	187	2
Compensation cost, net of taxes	30	34	29
Unrealized compensation cost on non-vested stock	$ 13
Unrealized compensation weighted average period non-vested stock	1.3
Nonvested Options Roll Forward [Abstract]
Non-vested, beginning of year (in shares)	28,800,000
Granted (in shares)	4,400,000
Vested (in shares)	(15,100,000)
Forfeited (in shares)	(500,000)
Non-vested, end of year (in shares)	17,600,000	28,800,000
Non-vested, beginning of year (weighted average grant date fair value)	$ 2.77
Granted (weighted average grant date fair value)	$ 8.48	$ 7.21	$ 1.07
Vested (weighted average grant date fair value)	$ 2.43
Forfeited (weighted average grant date fair value)	$ 2.79
Non-vested, end of year (weighted average grant date fair value)	$ 4.49	$ 2.77
Assumptions [Abstract]
Annualized dividend yield	0.00%	0.00%	0.00%
Expected volatility	53.20%	53.40%	52.00%
Risk-free interest rate	3.20%	3.00%	2.70%
Expected stock option term (in years)	7.1	6.9	6.0
Outstanding Options (in shares)	144,400,000
Exercisable Options (in shares)	126,800,000
$1.96 - $2.84 [Member] | Employee Stock Option [Member]
Assumptions [Abstract]
Outstanding Options (in shares)	22,400,000
Outstanding Options (weighted-average life (years))	7.20
Outstanding Options (weighted-average exercise price)	$ 2.10
Exercisable Options (in shares)	13,700,000
Exercisable Options (weighted-average exercise price)	$ 2.11
$5.11 - $10.18 [Member] | Employee Stock Option [Member]
Assumptions [Abstract]
Outstanding Options (in shares)	41,500,000
Outstanding Options (weighted-average life (years))	4.21
Outstanding Options (weighted-average exercise price)	$ 7.42
Exercisable Options (in shares)	41,500,000
Exercisable Options (weighted-average exercise price)	$ 7.42
$11.10 - $15.98 [Member] | Employee Stock Option [Member]
Assumptions [Abstract]
Outstanding Options (in shares)	48,300,000
Outstanding Options (weighted-average life (years))	3.85
Outstanding Options (weighted-average exercise price)	$ 13.20
Exercisable Options (in shares)	39,400,000
Exercisable Options (weighted-average exercise price)	$ 13.08
$16.09 - $17.05 [Member] | Employee Stock Option [Member]
Assumptions [Abstract]
Outstanding Options (in shares)	32,200,000
Outstanding Options (weighted-average life (years))	0.30
Outstanding Options (weighted-average exercise price)	$ 16.88
Exercisable Options (in shares)	32,200,000
Exercisable Options (weighted-average exercise price)	$ 16.88