Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, held-to-maturity	$ 50	$ 50
Fair Value, Inputs, Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, held-to-maturity	50	50
Senior Notes | Fair Value, Inputs, Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	1,260	2,252
Senior Notes | Fair Value, Inputs, Level 2 | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	$ 2,098	$ 2,097