Business Segment Information (Business Segment Financial Results) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Net interest income (expense) $ 549 $ 470
Provision for credit losses 12 16
Total noninterest income 244 271
Noninterest expenses 446 457
Provision (benefit) for income taxes (54) (66)
Net income (loss) 281 202
Net credit-related charge-offs (recoveries) 28 33
Assets, average 70,326 71,819
Loans, average 48,421 47,900
Deposits, average $ 56,090 $ 57,779
Return on average assets [1],[2] 1.62% 1.14%
Efficiency ratio [3],[4] 56.33% 61.71%
Tax benefits from employee stock transactions $ 19 $ 24
Business Bank    
Net interest income (expense) 330 332
Provision for credit losses 10 10
Total noninterest income 121 144
Noninterest expenses 184 197
Provision (benefit) for income taxes (59) (92)
Net income (loss) 198 177
Net credit-related charge-offs (recoveries) 18 30
Assets, average 38,911 38,091
Loans, average 37,368 36,754
Deposits, average $ 27,314 $ 29,648
Return on average assets [1] 2.07% 1.89%
Efficiency ratio [3] 40.72% 41.39%
Retail Bank    
Net interest income (expense) $ 165 $ 160
Provision for credit losses 4 12
Total noninterest income 42 48
Noninterest expenses 177 179
Provision (benefit) for income taxes (6) (6)
Net income (loss) 20 11
Net credit-related charge-offs (recoveries) 12 5
Assets, average 6,427 6,525
Loans, average 5,807 5,895
Deposits, average $ 24,064 $ 23,795
Return on average assets [1] 0.33% 0.18%
Efficiency ratio [3] 85.03% 86.01%
Wealth Management    
Net interest income (expense) $ 41 $ 41
Provision for credit losses (4) (1)
Total noninterest income 68 64
Noninterest expenses 72 70
Provision (benefit) for income taxes (10) (13)
Net income (loss) 31 23
Net credit-related charge-offs (recoveries) (2) (2)
Assets, average 5,373 5,406
Loans, average 5,246 5,251
Deposits, average $ 3,796 $ 3,978
Return on average assets [1] 2.30% 1.71%
Efficiency ratio [3] 67.10% 67.17%
Finance    
Net interest income (expense) $ 1 $ (71)
Provision for credit losses 0 0
Total noninterest income 11 11
Noninterest expenses (1) (1)
Provision (benefit) for income taxes (1) 24
Net income (loss) 12 (35)
Net credit-related charge-offs (recoveries) 0 0
Assets, average 13,779 13,944
Loans, average 0 0
Deposits, average 823 142
Other    
Net interest income (expense) 12 8
Provision for credit losses 2 (5)
Total noninterest income 2 4
Noninterest expenses 14 12
Provision (benefit) for income taxes [5] 22 21
Net income (loss) 20 26
Net credit-related charge-offs (recoveries) 0 0
Assets, average 5,836 7,853
Loans, average 0 0
Deposits, average $ 93 $ 216
[1] Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[2] Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[3] Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses).
[4] Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses).
[5] Included tax benefits from employee stock transactions of $19 million and $24 million for the three months ended March 31, 2018 and 2017, respectively.