v3.25.1
Securities - Distribution of Maturities of Debt Securities with Approximate Yield of Portfolio (Detail)
$ in Millions
Mar. 31, 2025
USD ($)
Debt Securities, Available-for-sale [Line Items]  
Available-for-sale amount within one year $ 2,978
Available-for-sale yield within one year (percent) 0.98%
Available-for-sale amount after one but within five years $ 7,375
Available-for-sale yield after one but within five years (percent) 3.73%
Available-for-sale amount after five but within ten years $ 2,875
Available-for-sale yield after five but within ten years (percent) 3.85%
Available-for-sale amount after ten years $ 14,826
Available-for-sale yield after ten years (percent) 2.62%
Total fair value within one year $ 2,972
Total fair value after one but within five years 7,340
Total fair value after five but within ten years 2,867
Total fair value after ten years 12,842
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year (percent) 0.00%
Held-to-maturity amount after one but within five years $ 2,634
Held-to-maturity yield after one but within five years (percent) 3.58%
Held-to-maturity after five but within ten years $ 995
Held-to-maturity yield after five but within ten years (percent) 3.76%
Held-to-maturity after ten years $ 14,510
Held-to-maturity yield after ten years (percent) 4.59%
Total fair value within one year $ 0
Total fair value after one but within five years 2,599
Total fair value after five but within ten years 952
Total fair value after ten years 14,085
U.S. Treasury  
Debt Securities, Available-for-sale [Line Items]  
Available-for-sale amount within one year $ 865
Available-for-sale yield within one year (percent) 1.24%
Available-for-sale amount after one but within five years $ 5,433
Available-for-sale yield after one but within five years (percent) 3.60%
Available-for-sale amount after five but within ten years $ 2,267
Available-for-sale yield after five but within ten years (percent) 4.05%
Available-for-sale amount after ten years $ 2,393
Available-for-sale yield after ten years (percent) 2.96%
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year (percent) 0.00%
Held-to-maturity amount after one but within five years $ 2,412
Held-to-maturity yield after one but within five years (percent) 3.65%
Held-to-maturity after five but within ten years $ 405
Held-to-maturity yield after five but within ten years (percent) 3.74%
Held-to-maturity after ten years $ 0
Held-to-maturity yield after ten years (percent) 0.00%
U.S. Government sponsored enterprises  
Debt Securities, Available-for-sale [Line Items]  
Available-for-sale amount within one year $ 47
Available-for-sale yield within one year (percent) 1.68%
Available-for-sale amount after one but within five years $ 170
Available-for-sale yield after one but within five years (percent) 1.49%
Available-for-sale amount after five but within ten years $ 326
Available-for-sale yield after five but within ten years (percent) 2.04%
Available-for-sale amount after ten years $ 4,514
Available-for-sale yield after ten years (percent) 1.82%
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year (percent) 0.00%
Held-to-maturity amount after one but within five years $ 219
Held-to-maturity yield after one but within five years (percent) 2.80%
Held-to-maturity after five but within ten years $ 580
Held-to-maturity yield after five but within ten years (percent) 3.73%
Held-to-maturity after ten years $ 340
Held-to-maturity yield after ten years (percent) 2.87%
U.S. Government agency issued or guaranteed  
Debt Securities, Available-for-sale [Line Items]  
Available-for-sale amount within one year $ 20
Available-for-sale yield within one year (percent) 0.81%
Available-for-sale amount after one but within five years $ 0
Available-for-sale yield after one but within five years (percent) 0.00%
Available-for-sale amount after five but within ten years $ 2
Available-for-sale yield after five but within ten years (percent) 4.20%
Available-for-sale amount after ten years $ 7,859
Available-for-sale yield after ten years (percent) 2.96%
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year (percent) 0.00%
Held-to-maturity amount after one but within five years $ 1
Held-to-maturity yield after one but within five years (percent) 4.56%
Held-to-maturity after five but within ten years $ 10
Held-to-maturity yield after five but within ten years (percent) 6.06%
Held-to-maturity after ten years $ 14,170
Held-to-maturity yield after ten years (percent) 4.63%
Obligations of U.S. states and political subdivisions  
Debt Securities, Available-for-sale [Line Items]  
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year (percent) 0.00%
Held-to-maturity amount after one but within five years $ 2
Held-to-maturity yield after one but within five years (percent) 3.78%
Held-to-maturity after five but within ten years $ 0
Held-to-maturity yield after five but within ten years (percent) 0.00%
Held-to-maturity after ten years $ 0
Held-to-maturity yield after ten years (percent) 0.00%
Asset-backed securities  
Debt Securities, Available-for-sale [Line Items]  
Available-for-sale amount within one year $ 0
Available-for-sale yield within one year (percent) 0.00%
Available-for-sale amount after one but within five years $ 48
Available-for-sale yield after one but within five years (percent) 4.41%
Available-for-sale amount after five but within ten years $ 47
Available-for-sale yield after five but within ten years (percent) 3.89%
Available-for-sale amount after ten years $ 60
Available-for-sale yield after ten years (percent) 5.33%
Foreign debt securities  
Debt Securities, Available-for-sale [Line Items]  
Available-for-sale amount within one year $ 2,046
Available-for-sale yield within one year (percent) 0.86%
Available-for-sale amount after one but within five years $ 1,724
Available-for-sale yield after one but within five years (percent) 4.34%
Available-for-sale amount after five but within ten years $ 233
Available-for-sale yield after five but within ten years (percent) 4.32%
Available-for-sale amount after ten years $ 0
Available-for-sale yield after ten years (percent) 0.00%