Derivative Financial Instruments - Mark-to-Market Impact of Derivatives on Statements of Income (Detail) - USD ($)
$ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2026

Sep. 30, 2025

Sep. 30, 2026

Sep. 30, 2025

Derivative Instruments Gain Loss [Line Items]

Mark-to-market gains (losses) recognized

$ 5

$ (4)

$ 11

$ (34)

Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax

Derivative Instruments Gain Loss [Line Items]

Mark-to-market gains (losses) recognized

14

(2)

32

(34)

Designated as Hedging Instrument [Member] | Fair Value [Member]

Derivative Instruments Gain Loss [Line Items]

Mark-to-market gains (losses) recognized

^[1],[2]

9

2

21

(0)

Designated as Hedging Instrument [Member] | Fair Value [Member] | Interest Rate Swaps [Member]

Derivative Instruments Gain Loss [Line Items]

Gains (losses) recognized in net income on derivatives

(96)

19

(124)

128

Gains (losses) recognized in net income on hedged items

103

(21)

134

(137)

Net fair value hedge ineffectiveness gains (losses)

7

(2)

10

(9)

Designated as Hedging Instrument [Member] | Fair Value [Member] | Cross-Currency Interest Rate Swaps [Member]

Derivative Instruments Gain Loss [Line Items]

Gains (losses) recognized in net income on derivatives

(4)

(1)

(19)

168

Gains (losses) recognized in net income on hedged items

6

5

30

(159)

Net fair value hedge ineffectiveness gains (losses)

2

4

11

9

Designated as Hedging Instrument [Member] | Cash Flow [Member]

Derivative Instruments Gain Loss [Line Items]

Mark-to-market gains (losses) recognized

^[2]

0

0

0

0

Trading [Member]

Derivative Instruments Gain Loss [Line Items]

Mark-to-market gains (losses) recognized

^[3]

5

(4)

11

(34)

Trading [Member] | Interest Rate Swaps [Member]

Derivative Instruments Gain Loss [Line Items]

Mark-to-market gains (losses) recognized

$ 5

$ (4)

$ 11

$ (34)

[1]	Recorded in interest expense in the consolidated statements of income.
[2]	The accrued interest income (expense) on fair value hedges and cash flow hedges is recorded in interest expense and is excluded from this table
[3]	Recorded in “gains (losses) on derivative and hedging activities, net” in the consolidated statements of income