Derivative Financial Instruments - Derivative Notional Values (Detail) - USD ($)	Jun. 30, 2026	Dec. 31, 2025
Derivative [Line Items]
Total Derivative Notional Values	$ 6,500,000,000	$ 7,300,000,000
Designated as Hedging Instrument [Member] \| Cash Flow [Member]
Derivative [Line Items]
Total Derivative Notional Values	1,200,000,000	1,300,000,000
Designated as Hedging Instrument [Member] \| Fair Value [Member]
Derivative [Line Items]
Total Derivative Notional Values	5,200,000,000	5,300,000,000
Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	100,000,000	700,000,000
Interest Rate Swaps [Member]
Derivative [Line Items]
Total Derivative Notional Values	5,400,000,000	6,100,000,000
Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow [Member]
Derivative [Line Items]
Total Derivative Notional Values	1,200,000,000	1,300,000,000
Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Fair Value [Member]
Derivative [Line Items]
Total Derivative Notional Values	4,100,000,000	4,100,000,000
Interest Rate Swaps [Member] \| Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	100,000,000	700,000,000
Cross-Currency Interest Rate Swaps [Member]
Derivative [Line Items]
Total Derivative Notional Values	1,100,000,000	1,200,000,000
Cross-Currency Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow [Member]
Derivative [Line Items]
Total Derivative Notional Values	0	0
Cross-Currency Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Fair Value [Member]
Derivative [Line Items]
Total Derivative Notional Values	1,100,000,000	1,200,000,000
Cross-Currency Interest Rate Swaps [Member] \| Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	$ 0	$ 0