Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Selected Quarterly Financial Data [Line Items]
Total revenues	$ 38,654	$ 35,943	$ 39,485	$ 37,718	$ 40,251	$ 38,144	$ 37,263	$ 33,900	$ 151,800	$ 149,558	$ 144,077
Income before income taxes	(1,117)	1,387	2,875	3,651	1,896	3,291	3,286	1,779	6,796	10,252	1,234
Net Income (Loss) Available to Common Stockholders, Basic	$ (783)	$ 957	$ 1,970	$ 2,452	$ 1,868	$ 2,192	$ 2,160	$ 1,153	4,596	$ 7,373	$ 1,231
Basic Common and Class B per share income from continuing operations	$ (0.20)	$ 0.24	$ 0.50	$ 0.62	$ 0.47	$ 0.55	$ 0.54	$ 0.29
Diluted Common and Class B per share income from continuing operations	$ (0.20)	$ 0.24	$ 0.49	$ 0.61	$ 0.47	$ 0.55	$ 0.54	$ 0.29
Material unusual or infrequently occurring items: [Abstract]
Remeasurement Gain/(Loss)	$ (3,000)				$ (698)
U.S. Tax Legislation on Foreign Currency Gains Losses On Non-U.S. Branch Operations [Member]
Material unusual or infrequently occurring items: [Abstract]
Deferred income tax expense/(benefit) and income tax credits	$ (300)								$ (300)
U.S. Tax Legislation in the Protecting Americans from Tax Hikes Act of 2015 [Domain]
Material unusual or infrequently occurring items: [Abstract]
Deferred income tax expense/(benefit) and income tax credits					$ (346)