XML 136 R126.htm IDEA: XBRL DOCUMENT v3.21.2
Fair Value Measurements - Additional Information Relating To Asset-Backed Securities and Collateralized Debt Obligations (Detail) - Level 3 [Member]
$ in Millions
Sep. 30, 2021
USD ($)
Asset-backed Securities Available-for-sale [Member] | BBB -B Rating [Member]  
Fair Value Of Other Financial Instrument [Line Items]  
Trading asset-backed securities and related collateral $ 101 [1]
Available-for-sale securities [Member]  
Fair Value Of Other Financial Instrument [Line Items]  
Trading asset-backed securities and related collateral 121
Alt [Member] | Home equity [Member] | AAA - A Rating [Member]  
Fair Value Of Other Financial Instrument [Line Items]  
Trading asset-backed securities and related collateral $ 20 [1]
[1] We utilize S&P as the primary source of credit ratings in the tables above. If S&P ratings are not available, ratings by Moody's and Fitch are used in that order.