Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	24.50%	31.10%
Current State and Local Tax Expense (Benefit)	$ 14
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle	4
Deferred Tax Assets, Net	$ 231		$ 250
Operating Loss Carryforwards, Valuation Allowance			$ 4