Restructuring Level 4 (Details) - Restructuring by Type - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2018	Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve			$ 6	$ 17
Other Liabilities, Current			106	135
Restructuring and Related Cost, Accelerated Depreciation			(4)	(14)	$ 129
Restructuring costs expected to be incurred			27
Cumulative restructuring costs, Incurred to Date			25
Restructuring and Related Cost, Cost Incurred this year			5
Accelerated Depreciation			4	14	129
Payments for Restructuring			(16)
Norco [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost				3	24
Other projects [Member]
Restructuring Cost and Reserve [Line Items]
Loss on Contract Termination					16
OTG [Domain]
Restructuring Cost and Reserve [Line Items]
Accelerated Depreciation				14	21
EPCD [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve			2	11
Restructuring costs expected to be incurred			14
Cumulative restructuring costs, Incurred to Date			13
Restructuring and Related Cost, Cost Incurred this year			1
Payments for Restructuring			(10)
FPD [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve			2	3
Restructuring costs expected to be incurred			9
Cumulative restructuring costs, Incurred to Date			8
Restructuring and Related Cost, Cost Incurred this year			3
Payments for Restructuring			(4)
Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve			2	$ 3
Restructuring costs expected to be incurred			4
Cumulative restructuring costs, Incurred to Date			4
Restructuring and Related Cost, Cost Incurred this year			1
Payments for Restructuring			$ (2)
OTG [Domain]
Restructuring Cost and Reserve [Line Items]
Impairment of Long-Lived Assets to be Disposed of	$ 20
Impairment of Intangible Assets (Excluding Goodwill)	5
Restructuring and Related Cost, Accelerated Depreciation	$ 25
Norco [Member]
Restructuring Cost and Reserve [Line Items]
Norco Restructuring and Related Cost, Accelerated Depreciation					76
Asset Retirement Obligation						$ 30
Accelerated depreciation related to asset retirement obligation					30
Asset Retirement Obligation, Revision of Estimate		$ 11			$ 11