Income Taxes Income Taxes - Effective Income Tax Expense Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ (1,606)	$ (6,684)	$ 1,120
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	(30)	(406)	68
Effective Income Tax Rate Reconciliation, Tax Contingency, State and Local, Amount	0	0	(114)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	1,423	2,727	74
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	23	(100)	(4)
Total Income Tax Expense (Benefit)	$ (190)	$ (4,463)	$ 1,144