Commitments and Contingencies - Environmental Matters (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2017
Loss Contingencies [Line Items]
Accrued expenses and other current liabilities	$ 8	$ 8
Deferred credits and other liabilities	26	28
Environmental remediation accrual, discounted basis	$ 34	$ 36
Weighted average discount rate	0.73%	1.30%
Expected payments of environmental remediation costs, 2021	$ 8
Expected payments of environmental remediation costs, 2022	3
Expected payments of environmental remediation costs, 2023	2
Expected payments of environmental remediation costs, 2024	2
Expected payments of environmental remediation costs, 2025	2
Expected payments of environmental remediation costs, thereafter	14
Expenditures for property, plant and equipment 2021	18
Expenditures for property, plant and equipment 2022	7
Estimated liability	1		$ 132
Payments for settlement	112	$ 79
Loss contingency accrual, period increase (decrease)	$ 11	$ 9