Financial Instruments - Fair Value Hedges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative liability, notional amount		$ 100,000,000
Unamortized balance of fair value adjustments - terminated swaps	$ 1,000,000	1,000,000
Amortization of fair value adjustments for terminated swaps	2,000,000	1,000,000	$ 3,000,000
Extinguishment of debt	2,000,000
Senior Note 2021
Derivative [Line Items]
Net asset fair value	4,000,000
Derivative liability, notional amount	200,000,000
Senior Note 2021 | Fair Value Hedging
Derivative [Line Items]
Ineffective Portion Recorded to Earnings Prior to Termination	0	$ 0	$ 0
Fair value adjustment to the hedged debt	$ 4,000,000