Summary of Significant Accounting Policies (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended								9 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Pre Twenty Eleven Restricted Stock Units	Sep. 30, 2012 Pre Twenty Eleven Restricted Stock Units	Sep. 30, 2012 Pre Twenty Eleven Restricted Stock Units Minimum	Sep. 30, 2012 Post-2011 RSUs	Sep. 30, 2011 Post-2011 RSUs	Sep. 30, 2012 Post-2011 RSUs	Sep. 30, 2011 Post-2011 RSUs	Sep. 30, 2012 Post-2011 RSUs Minimum	Sep. 30, 2012 Post-2011 RSUs Maximum	Sep. 30, 2012 Restricted Stock Units (RSUs)	Sep. 30, 2012 Restricted shares and stock options	Sep. 30, 2012 Class A Common Stock	Dec. 31, 2011 Class A Common Stock	Sep. 30, 2012 IPO Class A Common Stock	May 17, 2012 IPO Class A Common Stock	Sep. 30, 2012 IPO Convertible Preferred Stock Converted into Class B Common Stock	Sep. 30, 2012 IPO Class B Common Stock Converted into Class A Common Stock	Sep. 30, 2012 October Twenty Fifth Twenty Twelve Pre Twenty Eleven Restricted Stock Units	Sep. 30, 2012 November Fourteen Twenty Twelve Pre Twenty Eleven Restricted Stock Units
Summary Of Significant Accounting Policies
Common Stock, Shares, Issued																949	117		180
Price per share	$ 21.66		$ 21.66																$ 38
Proceeds from initial public offering, net																		$ 6,800,000,000
Underwriting discounts and commissions																		75,000,000
Other offering expenses																		7,000,000
Conversion of stock into common stock																				545	336
Restricted stock units, service period							4 years					4 years	5 years
Share based compensation expense	179,000,000	70,000,000	1,388,000,000	141,000,000	28,000,000	1,014,000,000		138,000,000	59,000,000	348,000,000	117,000,000
Future period share-based compensation expense	2,302,000,000		2,302,000,000		164,000,000	164,000,000		1,871,000,000		1,871,000,000				2,035,000,000	267,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			3 years			2 years				3 years
Withholding tax rate						45.00%
Expected Payments Related to Tax Withholding For Share Based Compensation					$ 2,600,000,000	$ 2,600,000,000
Share Based Compensation Arrangement By Share Based Payment Award Other Than Options Expected To Vest																						121	31
Expected Tax Withholding For Share Based Compensation																						99	20