Income Taxes Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Current Federal Tax Expense (Benefit)	$ 1,211	$ 1,190	$ 1,346
Current State and Local Tax Expense (Benefit)	168	169	206
Current Income Tax Expense (Benefit)	1,379	1,359	1,552
Deferred Federal Income Tax Expense (Benefit)	1,097	852	609
Deferred State and Local Income Tax Expense (Benefit)	51	89	(26)
Deferred Income Tax Expense (Benefit)	1,148	941	583
Income Tax Expense (Benefit), Continuing Operations	$ 2,527	$ 2,300	$ 2,135