Income Taxes Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Provision (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Current income tax provision (benefit)									$ (271)	$ 1,879	$ 3,067
Deferred income tax provision (benefit)									5,524	5,062	(48,482)
Provision (benefit) for federal income taxes	$ 1,103	$ 1,070	$ 2,210	$ 870	$ 818	$ 1,787	$ 1,752	$ 2,584	$ 5,253	$ 6,941	$ (45,415)
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Statutory corporate tax rate									35.00%	35.00%	35.00%
Equity investments in affordable housing projects									(2.60%)	(1.80%)	(1.50%)
Other									0.90%	1.40%	0.00%
Valuation allowance									(0.90%)	(1.80%)	(151.30%)
Effective tax rate									32.40%	32.80%	(117.80%)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount											$ (58,300)
Amended Tax Return [Member]
Income Tax note [Line Items]
Income Taxes Receivable, Current	$ 1,400								$ 1,400
Change in Deferred Tax Assets									$ (1,400)