Contingencies and Environmental Liabilities Contingencies and Environmental Liabilities - Patent Litigation - Narrative (Details) $ in Millions	1 Months Ended				12 Months Ended			36 Months Ended	84 Months Ended
	Jan. 31, 2018 USD ($)	Feb. 28, 2017 USD ($)	Dec. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) patent	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2026	Dec. 31, 2023
Loss Contingencies [Line Items]
Litigation settlement		$ (80)			$ 0	$ (625)	$ 0
Number of Patents Involved in Legal Dispute | patent					2
Percentage of settlement to be paid to third-party (as percent)					20.00%
Litigation Settlement, Amount Awarded from Other Party			$ 2,540	$ 200
Forecast
Loss Contingencies [Line Items]
Royalty rate (as percent)								2.50%	6.50%
Patent litigation
Loss Contingencies [Line Items]
Litigation settlement						$ 117
Subsequent Event
Loss Contingencies [Line Items]
Litigation settlement	$ 115