Summary of Significant Accounting Policies - Recently Issued and Adopted Accounting Pronouncement (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncement, Early Adoption [Line Items]
Net cumulative-effect adjustment							$ 1,705
Consolidated Balance Sheets Data:
Other assets	$ 990	$ 935	$ 886	$ 935	$ 990	$ 1,312	796
Total assets	60,007	55,968	52,262	55,968	60,007	64,961	49,407
Other liabilities	2,290	2,170	1,867	2,170	2,290	2,892	3,157
Total liabilities	4,886	4,373	3,674	4,373	4,886	5,767	5,189
Common stock and additional paid-in capital	37,391	36,494	35,673	36,494	37,391
Retained earnings	18,102	15,475	13,191	15,475	18,102	21,670	9,787
Consolidated Statements of Income Data:
Share-based compensation included in costs and expenses	824	817	746			3,218	2,969	$ 1,837
Total costs and expenses	3,894	3,702	3,372			15,211	11,703	7,472
Provision for income taxes	537	471	328			2,301	2,506	1,970
Net income	$ 2,627	$ 2,283	$ 1,738			$ 10,217	$ 3,688	$ 2,940
Effective tax rate	17.00%	17.00%	16.00%			18.40%	40.40%	40.10%
Earnings per share attributable to Class A and Class B common stockholders:
Basic (in dollars per share)	$ 0.91	$ 0.80	$ 0.61			$ 3.56	$ 1.31	$ 1.12
Diluted (in dollars per share)	$ 0.90	$ 0.78	$ 0.60			$ 3.49	$ 1.29	$ 1.10
Weighted average shares used to compute earnings per share attributable to Class A and Class B common stockholders:
Diluted (in shares)	2,931	2,921	2,905			2,925	2,853	2,664
Consolidated Statements of Cash Flows Data:
Net cash provided by operating activities			$ 3,477	7,142	11,178	$ 16,108	$ 10,320	$ 7,326
Net cash provided by (used in) financing activities			(310)	(306)	(314)	(310)	(139)	(298)
As Reported
Consolidated Balance Sheets Data:
Other assets	$ 660	$ 703	700	703	660
Total assets	59,674	55,739	52,075	55,739	59,674
Other liabilities	2,964	3,145	3,116	3,145	2,964
Total liabilities	5,559	5,356	4,925	5,356	5,559
Common stock and additional paid-in capital	38,756	37,405	36,129	37,405	38,756
Retained earnings	15,731	13,352	11,297	13,352	15,731
Consolidated Statements of Income Data:
Share-based compensation included in costs and expenses	819	805	747
Total costs and expenses	3,889	3,690	3,373
Provision for income taxes	790	711	555
Net income	$ 2,379	$ 2,055	$ 1,510
Effective tax rate	25.00%	26.00%	27.00%
Earnings per share attributable to Class A and Class B common stockholders:
Basic (in dollars per share)	$ 0.83	$ 0.72	$ 0.53
Diluted (in dollars per share)	$ 0.82	$ 0.71	$ 0.52
Weighted average shares used to compute earnings per share attributable to Class A and Class B common stockholders:
Diluted (in shares)	2,915	2,904	2,888
Consolidated Statements of Cash Flows Data:
Net cash provided by operating activities			$ 2,983	6,181	9,758
Net cash provided by (used in) financing activities			$ 184	$ 655	$ 1,106
Accounting Standards Update 2016-09, Excess Income Tax Benefit Component | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease to cash provided by financing activities							1,720	1,870
Increase to cash provided by operating activities							1,720	1,870
Accounting Standards Update ASU 2016-09, Income Tax Expense (Benefit) | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Accounting Standards Update ASU 2016-09, Income Tax Expense (Benefit)						934
Retained Earnings
New Accounting Pronouncement, Early Adoption [Line Items]
Net cumulative-effect adjustment							1,666
Consolidated Statements of Income Data:
Net income						$ 10,217	$ 3,688	$ 2,940