Discontinued Operations Discontinued Operations Cash Flow (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Operating Activities, Discontinued Operations	[1]	$ 44	$ 143
Capital Expenditure, Discontinued Operations		$ (29)	$ (175)

[1] (a) Excluding income taxes and changes to working capital.