CONSOLIDATED STATEMENT OF CASH FLOWS (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Statement of Cash Flows [Abstract]
Cash at beginning/end of period, discontinued operations	$ 5	$ 7	$ 11	$ 12