XML 64 R52.htm IDEA: XBRL DOCUMENT v3.8.0.1
Securities - Distribution of maturities of debt securities with approximate yield of portfolio (Detail)
$ in Millions
Mar. 31, 2018
USD ($)
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Available-for-sale amount within one year $ 1,026
Available-for-sale yield within one year 1.57%
Available-for-sale amount after one but within five years $ 6,933
Available-for-sale yield after one but within five years 2.42%
Available-for-sale amount after five but within ten years $ 10,271
Available-for-sale yield after five but within ten years 2.18%
Available-for-sale amount after ten years $ 12,529
Available-for-sale yield after ten years 2.80%
Total fair value within one year $ 1,030
Total fair value after one but within five years 6,965
Total fair value after five but within ten years 9,938
Total fair value after ten years 12,290
Held-to-maturity amount within one year $ 1
Held-to-maturity yield within one year 4.25%
Held-to-maturity amount after one but within five years $ 347
Held-to-maturity yield after one but within five years 2.66%
Held-to-maturity after five but within ten years $ 316
Held-to-maturity yield after five but within ten years 2.87%
Held-to-maturity after ten years $ 13,610
Held-to-maturity yield after ten years 2.55%
Total fair value within one year $ 1
Total fair value after one but within five years 344
Total fair value after five but within ten years 313
Total fair value after ten years 13,347
U.S. Treasury [Member]  
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Available-for-sale amount within one year $ 0
Available-for-sale yield within one year 0.00%
Available-for-sale amount after one but within five years $ 3,392
Available-for-sale yield after one but within five years 2.22%
Available-for-sale amount after five but within ten years $ 8,255
Available-for-sale yield after five but within ten years 2.07%
Available-for-sale amount after ten years $ 3,200
Available-for-sale yield after ten years 3.04%
US Government sponsored enterprises [Member]  
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Available-for-sale amount within one year $ 225
Available-for-sale yield within one year 3.54%
Available-for-sale amount after one but within five years $ 2,588
Available-for-sale yield after one but within five years 3.03%
Available-for-sale amount after five but within ten years $ 1,998
Available-for-sale yield after five but within ten years 2.64%
Available-for-sale amount after ten years $ 2,877
Available-for-sale yield after ten years 2.79%
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year 0.00%
Held-to-maturity amount after one but within five years $ 322
Held-to-maturity yield after one but within five years 2.57%
Held-to-maturity after five but within ten years $ 280
Held-to-maturity yield after five but within ten years 2.77%
Held-to-maturity after ten years $ 2,627
Held-to-maturity yield after ten years 2.86%
US Government agency issued or guaranteed [Member]  
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Available-for-sale amount within one year $ 50
Available-for-sale yield within one year 1.87%
Available-for-sale amount after one but within five years $ 67
Available-for-sale yield after one but within five years 2.06%
Available-for-sale amount after five but within ten years $ 18
Available-for-sale yield after five but within ten years 4.00%
Available-for-sale amount after ten years $ 6,297
Available-for-sale yield after ten years 2.64%
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year 0.00%
Held-to-maturity amount after one but within five years $ 20
Held-to-maturity yield after one but within five years 3.86%
Held-to-maturity after five but within ten years $ 31
Held-to-maturity yield after five but within ten years 3.57%
Held-to-maturity after ten years $ 10,979
Held-to-maturity yield after ten years 2.47%
Obligations of U.S. states and political subdivision [Member]  
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Held-to-maturity amount within one year $ 1
Held-to-maturity yield within one year 4.25%
Held-to-maturity amount after one but within five years $ 5
Held-to-maturity yield after one but within five years 3.61%
Held-to-maturity after five but within ten years $ 5
Held-to-maturity yield after five but within ten years 4.57%
Held-to-maturity after ten years $ 1
Held-to-maturity yield after ten years 4.41%
Asset backed securities [Member]  
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Available-for-sale amount within one year $ 200
Available-for-sale yield within one year 3.17%
Available-for-sale amount after one but within five years $ 0
Available-for-sale yield after one but within five years 0.00%
Available-for-sale amount after five but within ten years $ 0
Available-for-sale yield after five but within ten years 0.00%
Available-for-sale amount after ten years $ 155
Available-for-sale yield after ten years 4.22%
Held-to-maturity amount within one year $ 0
Held-to-maturity yield within one year 0.00%
Held-to-maturity amount after one but within five years $ 0
Held-to-maturity yield after one but within five years 0.00%
Held-to-maturity after five but within ten years $ 0
Held-to-maturity yield after five but within ten years 0.00%
Held-to-maturity after ten years $ 3
Held-to-maturity yield after ten years 6.25%
Foreign debt securities [Member]  
Schedule of Available-for-sale and Held-to-Maturity Securities [Line Items]  
Available-for-sale amount within one year $ 551
Available-for-sale yield within one year 0.16%
Available-for-sale amount after one but within five years $ 886
Available-for-sale yield after one but within five years 1.40%
Available-for-sale amount after five but within ten years $ 0
Available-for-sale yield after five but within ten years 0.00%
Available-for-sale amount after ten years $ 0
Available-for-sale yield after ten years 0.00%