Fair Value - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments in equity securities	$ 127	$ 129
Available-for-sale debt securities	138	110
Trading securities	12	12
Total assets	277	251
Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments in equity securities	127	129
Total assets	127	129
Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	138	110
Trading securities	12	12
Total assets	$ 150	$ 122