Financial Instruments - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Foreign exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 1,655	$ 1,386
Interest rate caps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	11,900	8,871
Interest rate caps | Subsidiary Issuers
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	3,000	3,100
Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	1,450	1,950
Interest rate caps sold
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	7,200	6,000
Purchase
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 4,700	$ 2,900