Stockholders Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended												12 Months Ended
	Dec. 31, 2012 Y	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Class A Common Stock	Jun. 21, 2012 Class A Common Stock	Dec. 31, 2011 Class A Common Stock	Dec. 31, 2012 Class B Common Stock	Jun. 21, 2012 Class B Common Stock	Dec. 31, 2011 Class B Common Stock	Dec. 31, 2012 Class C Capital Stock	Jun. 21, 2012 Class C Capital Stock	Dec. 31, 2011 Class C Capital Stock	Dec. 31, 2012 Employee stock options	Dec. 31, 2011 Employee stock options	Dec. 31, 2010 Employee stock options	Dec. 31, 2012 Restricted Stock Units (RSUs)	Dec. 31, 2011 Restricted Stock Units (RSUs)	Dec. 31, 2010 Restricted Stock Units (RSUs)
Stockholders Equity Note [Line Items]
Convertible preferred stock, shares authorized	100,000,000	100,000,000
Convertible preferred stock, par value	$ 0.001	$ 0.001
Convertible preferred stock, shares issued	0	0
Convertible preferred stock, shares outstanding	0	0
Number of authorized classes of common stock	2
Common stock, shares authorized	12,000,000,000	9,000,000,000		9,000,000,000	9,000,000,000	6,000,000,000	3,000,000,000		3,000,000,000
Common stock, shares outstanding	329,979,000	324,895,000		267,448,281		257,553,000	62,530,474		67,342,000
Common stock, Par value	$ 0.001	$ 0.001		$ 0.001	$ 0.001		$ 0.001	$ 0.001
Common stock, entitled votes per share				1			10
Capital stock, shares authorized										3,000,000,000	3,000,000,000	3,000,000,000
Capital stock, par value										$ 0.001	$ 0.001	$ 0.001
Stock Plans, terms													10 years	10 years	10 years
Stock Plans, vesting period													4 years	4 years	4 years	4 years	4 years	4 years
Stock Plans, shares of common stock reserved for future issuance	15,833,050	21,794,492
Warrants held by selected financial institutions that were options purchased from employees under our Transferable Stock Option (TSO) program	1,600,000
Warrants held by selected financial institutions that were options purchased from employees under our Transferable Stock Option (TSO) program, weighted-average exercise price	$ 363.66
Warrants held by selected financial institutions that were options purchased from employees under our Transferable Stock Option (TSO) program, weighted-average remaining life (in years)	1.3
Number of shares underlying TSOs sold to selected financial institutions under the TSO program	1,226,983
Number of shares underlying TSOs sold to selected financial institutions under the TSO program, total value	$ 365
Number of shares underlying TSOs sold to selected financial institutions under the TSO program, average per share price	$ 297.28
Number of shares underlying TSOs sold to selected financial institutions under the TSO program, average premium per share price	$ 9.35
Total grant date fair value of stock options vested	489	561	690
Aggregate intrinsic value of all options and warrants exercised	827	674	794
Unrecognized compensation cost													$ 386			$ 4,800
Unrecognized compensation cost related to stock awards, weighted-average period													2 years 2 months 12 days			2 years 8 months 12 days