Acquisitions and Dispositions - Discontinued Operations (Details) - USD ($) $ in Millions	2 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of discontinued operations, net of tax						$ 279	$ 0	$ 0	$ 0	$ 0	$ 279	$ 0
(Loss) income from discontinued operations, net of tax		$ 1	$ 0	$ (10)	$ 0	$ 0	$ 6	$ 7	$ 7	(9)	20	15
Cash inflow from discontinued operations	$ 102
L&W Supply
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales										510
Cash inflow from discontinued operations										489
Sales sold to third party customers											568	531
L&W Supply | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration for discontinued operations													$ 675
Gain on sale of discontinued operations, net of tax											279	$ 0
(Loss) income from discontinued operations, net of tax										(8)
European Operations | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax										$ (1)	$ (2)