Earnings per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator
Net income	$ 806	$ 425	$ 2,239	$ 977
Less: Net income attributable to participating securities	4	3	10	6
Net income attributable to Class A and Class B common stockholders	802	422	2,229	971
Denominator
Number of shares used for basic EPS computation (in shares)	2,587	2,430	2,565	2,408
Basic EPS (in dollars per share)	$ 0.31	$ 0.17	$ 0.87	$ 0.40
Numerator
Net income attributable to common stockholders	802	422	2,229	971
Denominator
Number of shares used for basic EPS computation (in shares)	2,587	2,430	2,565	2,408
Number of shares used for diluted EPS computation (in shares)	2,644	2,528	2,616	2,504
Diluted EPS (in dollars per share)	$ 0.30	$ 0.17	$ 0.86	$ 0.39
Class A Common Stock
Numerator
Net income	632	320	1,747	717
Less: Net income attributable to participating securities	3	2	8	4
Net income attributable to Class A and Class B common stockholders	629	318	1,739	713
Denominator
Weighted average shares outstanding (in shares)	2,032	1,833	2,006	1,773
Less: Shares subject to repurchase (in shares)	4	6	5	5
Number of shares used for basic EPS computation (in shares)	2,028	1,827	2,001	1,768
Basic EPS (in dollars per share)	$ 0.31	$ 0.17	$ 0.87	$ 0.40
Numerator
Net income attributable to common stockholders	629	318	1,739	713
Reallocation of net income attributable to participating securities	4	3	10	6
Reallocation of net income as a result of conversion of Class B to Class A common stock	173	104	490	258
Reallocation of net income to Class B common stock	0	0	0	0
Net income attributable to common stockholders for diluted EPS	806	425	2,239	977
Denominator
Number of shares used for basic EPS computation (in shares)	2,028	1,827	2,001	1,768
Conversion of Class B to Class A common stock (in shares)	559	603	564	640
Shares subject to repurchase (in shares)	8	6	6	6
Number of shares used for diluted EPS computation (in shares)	2,644	2,528	2,616	2,504
Diluted EPS (in dollars per share)	$ 0.30	$ 0.17	$ 0.86	$ 0.39
Class A Common Stock | Employee Stock Options
Denominator
Share based payment arrangements (in shares)	13	59	13	69
Class A Common Stock | Restricted Stock Units (RSUs)
Denominator
Share based payment arrangements (in shares)	36	33	32	21
Class B Common Stock
Numerator
Net income	174	105	492	260
Less: Net income attributable to participating securities	1	1	2	2
Net income attributable to Class A and Class B common stockholders	173	104	490	258
Denominator
Weighted average shares outstanding (in shares)	567	611	570	649
Less: Shares subject to repurchase (in shares)	8	8	6	9
Number of shares used for basic EPS computation (in shares)	559	603	564	640
Basic EPS (in dollars per share)	$ 0.31	$ 0.17	$ 0.87	$ 0.40
Numerator
Net income attributable to common stockholders	173	104	490	258
Reallocation of net income attributable to participating securities	0	0	0	0
Reallocation of net 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	7	13	18	29
Net income attributable to common stockholders for diluted EPS	$ 180	$ 117	$ 508	$ 287
Denominator
Number of shares used for basic EPS computation (in shares)	559	603	564	640
Conversion of Class B to Class A common stock (in shares)	0	0	0	0
Shares subject to repurchase (in shares)	5	6	3	6
Number of shares used for diluted EPS computation (in shares)	591	701	593	736
Diluted EPS (in dollars per share)	$ 0.30	$ 0.17	$ 0.86	$ 0.39
Class B Common Stock | Employee Stock Options
Denominator
Share based payment arrangements (in shares)	13	59	13	69
Class B Common Stock | Restricted Stock Units (RSUs)
Denominator
Share based payment arrangements (in shares)	14	33	13	21