Derivative Financial Instruments - Impact of Derivatives on Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative Assets:
Derivative assets	$ 55	$ 56
Derivative Liabilities:
Derivative liabilities	(190)	(258)
Net total derivatives	(135)	(202)
Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative Assets:
Derivative assets	0	0
Derivative Liabilities:
Derivative liabilities	0	0
Net total derivatives	0	0
Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Assets:
Derivative assets	55	55
Derivative Liabilities:
Derivative liabilities	(189)	(255)
Net total derivatives	(134)	(200)
Trading [Member]
Derivative Assets:
Derivative assets	0	1
Derivative Liabilities:
Derivative liabilities	(1)	(3)
Net total derivatives	(1)	(2)
Interest Rate Swaps [Member]
Derivative Assets:
Derivative assets	55	56
Derivative Liabilities:
Derivative liabilities	(1)	(5)
Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative Assets:
Derivative assets	0	0
Derivative Liabilities:
Derivative liabilities	0	0
Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Assets:
Derivative assets	55	55
Derivative Liabilities:
Derivative liabilities	0	(2)
Interest Rate Swaps [Member] | Trading [Member]
Derivative Assets:
Derivative assets	0	1
Derivative Liabilities:
Derivative liabilities	(1)	(3)
Cross-Currency Interest Rate Swaps [Member]
Derivative Assets:
Derivative assets	0	0
Derivative Liabilities:
Derivative liabilities	(189)	(253)
Cross-Currency Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative Assets:
Derivative assets	0	0
Derivative Liabilities:
Derivative liabilities	0	0
Cross-Currency Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Assets:
Derivative assets	0	0
Derivative Liabilities:
Derivative liabilities	(189)	(253)
Cross-Currency Interest Rate Swaps [Member] | Trading [Member]
Derivative Assets:
Derivative assets	0	0
Derivative Liabilities:
Derivative liabilities	0	0
Floor Income Contracts [Member]
Derivative Liabilities:
Derivative liabilities	0	0
Floor Income Contracts [Member] | Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative Liabilities:
Derivative liabilities	0	0
Floor Income Contracts [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Liabilities:
Derivative liabilities	0	0
Floor Income Contracts [Member] | Trading [Member]
Derivative Liabilities:
Derivative liabilities	$ 0	$ 0