(Loss) Earnings per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator
Net (loss) income	$ (59)	$ 227	$ (11)	$ 698
Less: Net income attributable to participating securities	0	77	0	235
Net (loss) income attributable to common stockholders	(59)	150	(11)	463
Denominator
Number of shares used for basic EPS computation	2,420	1,316	1,884	1,283
Basic EPS	$ 0.02	$ (0.11)	$ 0.01	$ (0.36)
Numerator
Net (loss) income attributable to common stockholders	(59)	150	(11)	463
Denominator
Number of shares used for basic EPS computation	2,420	1,316	1,884	1,283
Number of shares used for diluted EPS computation	2,420	1,520	1,884	1,507
Diluted EPS	$ 0.02	$ (0.10)	$ 0.01	$ (0.32)
Class A Common Stock
Numerator
Net (loss) income	(19)	19	(3)	58
Less: Net income attributable to participating securities	0	7	0	20
Net (loss) income attributable to common stockholders	(19)	12	(3)	38
Denominator
Weighted average shares outstanding	794	113	431	107
Less: Shares subject to repurchase	1	1	1	0
Number of shares used for basic EPS computation	793	112	430	107
Basic EPS	$ (0.02)	$ 0.11	$ (0.01)	$ 0.36
Numerator
Net (loss) income attributable to common stockholders	(19)	12	(3)	38
Reallocation of net income attributable to participating securities	0	6	0	22
Reallocation of net (loss) income as a result of conversion of Class B to Class A common stock	(40)	138	(8)	425
Reallocation of net income to Class B common stock	0	0	0	0
Net (loss) income attributable to common stockholders for diluted EPS	(59)	156	(11)	485
Denominator
Number of shares used for basic EPS computation	793	112	430	107
Conversion of Class B to Class A common stock	1,627	1,204	1,454	1,176
Shares subject to repurchase	0	4	0	4
Warrants	0	2	0	3
Number of shares used for diluted EPS computation	2,420	1,520	1,884	1,507
Diluted EPS	$ (0.02)	$ 0.10	$ (0.01)	$ 0.32
Class A Common Stock | Employee Stock Option
Denominator
Share based payment arrangements	0	188	0	212
Class A Common Stock | Restricted Stock
Denominator
Share based payment arrangements	0	10	0	5
Class B Common Stock
Numerator
Net (loss) income	(40)	208	(8)	640
Less: Net income attributable to participating securities	0	70	0	215
Net (loss) income attributable to common stockholders	(40)	138	(8)	425
Denominator
Weighted average shares outstanding	1,632	1,208	1,457	1,181
Less: Shares subject to repurchase	5	4	3	5
Number of shares used for basic EPS computation	1,627	1,204	1,454	1,176
Basic EPS	$ (0.02)	$ 0.11	$ (0.01)	$ 0.36
Numerator
Net (loss) income attributable to common stockholders	(40)	138	(8)	425
Reallocation of net income attributable to participating securities	0	0	0	0
Reallocation of net (loss) income as a result of conversion of Class B to Class A common stock	0	0	0	0
Reallocation of net income to Class B common stock	0	8	0	26
Net (loss) income attributable to common stockholders for diluted EPS	$ (40)	$ 146	$ (8)	$ 451
Denominator
Number of shares used for basic EPS computation	1,627	1,204	1,454	1,176
Conversion of Class B to Class A common stock	0	0	0	0
Shares subject to repurchase	0	4	0	4
Warrants	0	2	0	3
Number of shares used for diluted EPS computation	1,627	1,408	1,454	1,400
Diluted EPS	$ (0.02)	$ 0.10	$ (0.01)	$ 0.32
Class B Common Stock | Employee Stock Option
Denominator
Share based payment arrangements	0	188	0	212
Class B Common Stock | Restricted Stock
Denominator
Share based payment arrangements	0	10	0	5