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Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
Share data in Millions, except Per Share data, unless otherwise specified |
3 Months Ended | 6 Months Ended | 3 Months Ended | 6 Months Ended | 6 Months Ended | 6 Months Ended | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Jun. 30, 2012
|
Jun. 30, 2011
|
Jun. 30, 2012
|
Jun. 30, 2011
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Jun. 30, 2012
Pre Twenty Eleven Restricted Stock Units
|
Jun. 30, 2012
Pre Twenty Eleven Restricted Stock Units
Minimum
|
Jun. 30, 2012
Pre Twenty Eleven Restricted Stock Units
Maximum
|
Jun. 30, 2012
Post-2011 RSUs
|
Jun. 30, 2011
Post-2011 RSUs
|
Jun. 30, 2012
Post-2011 RSUs
|
Jun. 30, 2011
Post-2011 RSUs
|
Jun. 30, 2012
Post-2011 RSUs
Minimum
|
Jun. 30, 2012
Post-2011 RSUs
Maximum
|
Jun. 30, 2012
Restricted Stock Units (RSUs)
|
Jun. 30, 2012
Restricted shares and stock options
|
Jun. 30, 2012
Common Class A
|
Dec. 31, 2011
Common Class A
|
Jun. 30, 2012
IPO
Common Class A
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May 17, 2012
IPO
Common Class A
|
Jun. 30, 2012
IPO
Convertible Preferred Stock Converted into Class B Common Stock
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Jun. 30, 2012
IPO
Class B Common Stock Converted into Class A Common Stock
|
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| Summary Of Significant Accounting Policies [Line Items] | |||||||||||||||||||||
| Shares issued, initial public offering | 641 | 117 | 180 | ||||||||||||||||||
| Initial public offering, price per share | $ 38.00 | ||||||||||||||||||||
| Proceeds from initial public offering, net | $ 6,800,000,000 | ||||||||||||||||||||
| Underwriting discounts and commissions | 75,000,000 | ||||||||||||||||||||
| Other offering expenses | 6,000,000 | ||||||||||||||||||||
| Conversion of stock into common stock | 545 | 336 | |||||||||||||||||||
| Future period share-based compensation expense | 2,245,000,000 | 2,245,000,000 | 205,000,000 | 1,959,000,000 | 1,959,000,000 | 2,164,000,000 | 81,000,000 | ||||||||||||||
| Weighted-average period over which share-based compensation expense will be recognized | 2 years | 2 years | 2 years | ||||||||||||||||||
| Share based compensation expense | $ 1,106,000,000 | $ 64,000,000 | $ 1,209,000,000 | $ 71,000,000 | $ 986,000,000 | $ 113,000,000 | $ 58,000,000 | $ 210,000,000 | $ 58,000,000 | ||||||||||||
| Restricted stock units, service period | 4 years | 5 years | |||||||||||||||||||
| Share based compensation, number of shares vested | 273 | ||||||||||||||||||||
| Share based compensation, vesting period | Oct. 15, 2012 | Nov. 14, 2012 | |||||||||||||||||||
| Withholding tax rate | 45.00% | ||||||||||||||||||||