Investments of Insurance Subsidiaries - Schedule of Investments (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amounts classified as current assets	$ (103)	$ (116)
Investment carrying value	438	388
Amortized Cost	525	472
Unrealized Amounts, Gains	18	32
Unrealized Amounts, Losses	(2)
Fair Value	541	504
Money Market Funds and Other [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	125	88
Fair Value	125	88
Debt Securities [Member] \| States and Municipalities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	400	384
Unrealized Amounts, Gains	18	32
Unrealized Amounts, Losses	(2)
Fair Value	$ 416	$ 416

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