v3.21.2
Loans - Fair value of loans held for investment by level (Detail) - USD ($)
$ in Millions
Jun. 30, 2021
Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans $ 12,516 $ 13,625
Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 10,287 10,947
Level 3 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 2,229 2,678
Corporate [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 2,786 2,751
Corporate [Member] | Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 1,934 1,822
Corporate [Member] | Level 3 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 852 929
Wealth management [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 7,122 7,872
Wealth management [Member] | Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 7,059 7,809
Wealth management [Member] | Level 3 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 63 63
Commercial real estate [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 1,677 1,961
Commercial real estate [Member] | Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 757 857
Commercial real estate [Member] | Level 3 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 920 1,104
Residential real estate [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 417 494
Residential real estate [Member] | Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 299 234
Residential real estate [Member] | Level 3 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 118 260
Other [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 514 547
Other [Member] | Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans 238 225
Other [Member] | Level 3 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans $ 276 $ 322