Accumulated Other Comprehensive Loss - Tax Impact (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	$ 0
Amounts reclassified from accumulated other comprehensive (income) loss, tax	3
Available-for-Sale Debt Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	(1)
Amounts reclassified from accumulated other comprehensive (income) loss, tax	0
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	0
Amounts reclassified from accumulated other comprehensive (income) loss, tax	0
Post - Retirement Benefit Obligation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	0
Amounts reclassified from accumulated other comprehensive (income) loss, tax	$ 0