Stockholders' Equity Table of Changes in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance	$ (238)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	1,862
Other comprehensive income (loss)	30	$ 100	$ 172
Total, Ending Balance	(270)	(238)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance	(2)
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(3)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(2)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5
Other comprehensive income (loss)	3
Total, Ending Balance	(2)	(2)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance	(1)
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0
Other comprehensive income (loss)	0
Total, Ending Balance	(1)	(1)
Pension and Other Post Retirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance	(235)
Cumulative Effect of New Accounting Principle in Period of Adoption				(61)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	35
Other comprehensive income (loss)	29
Total, Ending Balance	(267)	(235)
Total AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance	(238)
Cumulative Effect of New Accounting Principle in Period of Adoption				$ (61)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(3)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(8)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	40
Other comprehensive income (loss)	32	101	$ 103
Total, Ending Balance	$ (270)	$ (238)