Stockholders' Equity Table Of Reclassifications from AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit	$ 55	$ 37
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	0
Pension and Other Postretirement Benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	5
Foreign Currency Translation
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	0
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit	(1)
Amounts reclassified from accumulated other comprehensive income (loss)	5
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension and Other Postretirement Benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of actuarial (gain) loss included in net periodic benefit cost (credit)	$ 6