Change In Accounting Estimate (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares
Change in Accounting Estimate [Abstract]
Change in Accounting Estimate Financial Effect on Depreciation Expense, Depreciation Estimate	$ 28
Change in Accounting Estimate, Financial Effect on Net Income, Depreciation Adjustment	$ (15)
Change in Accounting Estimate Financial Effect on Net Income Per Share | $ / shares	$ (0.02)