v3.25.2
Fair Value Measurements - Assets and Liabilities Recorded as Fair Value on Nonrecurring Basis (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total Gains (Losses) $ (13) $ (57) $ (64) $ (59)  
Consumer loans          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total Gains (Losses) 2 1 3 2  
Commercial loans held for sale          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total Gains (Losses)   0   2  
Commercial Loans          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total Gains (Losses) (15) (46) (67) (48)  
Leases          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total Gains (Losses)   $ (12)   $ (15)  
Fair Value, Nonrecurring          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 605   605   $ 450
Fair Value, Nonrecurring | Level 1          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 0   0   0
Fair Value, Nonrecurring | Level 2          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 96   96   100
Fair Value, Nonrecurring | Level 3          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 509   509   350
Fair Value, Nonrecurring | Consumer loans          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 96   96   100
Fair Value, Nonrecurring | Consumer loans | Level 1          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 0   0   0
Fair Value, Nonrecurring | Consumer loans | Level 2          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 96   96   100
Fair Value, Nonrecurring | Consumer loans | Level 3          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 0   0   0
Fair Value, Nonrecurring | Commercial loans held for sale          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Commercial loans held for sale | Level 1          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Commercial loans held for sale | Level 2          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Commercial loans held for sale | Level 3          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Commercial Loans          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 509   509   350
Fair Value, Nonrecurring | Commercial Loans | Level 1          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 0   0   0
Fair Value, Nonrecurring | Commercial Loans | Level 2          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis 0   0   0
Fair Value, Nonrecurring | Commercial Loans | Level 3          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis $ 509   $ 509   350
Fair Value, Nonrecurring | Leases          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Leases | Level 1          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Leases | Level 2          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         0
Fair Value, Nonrecurring | Leases | Level 3          
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]          
Total assets at fair value on a non-recurring basis         $ 0