v3.10.0.1
Employee Benefit Plans (Net Periodic Benefit Expense (Income)) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Amounts Recognized in Other Comprehensive Loss (Income) on Pre-tax Basis      
Description of amortization of unrealized net gains and losses The Firm generally amortizes into net periodic benefit expense (income) the unrecognized net gains and losses exceeding 10% of the greater of the projected benefit obligation or the market-related value of plan assets.    
Pension Plans      
Components of Net Periodic Benefit Expense (Income)      
Service cost, benefits earned during the period $ 16 $ 16 $ 17
Interest cost on projected benefit obligation 134 146 150
Expected return on plan assets (112) (117) (122)
Net amortization of prior service credit (1) 0 0
Net amortization of actuarial loss 26 17 12
Net periodic benefit expense (income) 63 62 57
Amounts Recognized in Other Comprehensive Loss (Income) on Pre-tax Basis      
Beginning balance (947) (761) (625)
Net gain (loss) 158 (205) (149)
Prior service credit (cost) (15) 2 1
Amortization of prior service credit (1) 0 0
Amortization of net loss 26 17 12
Changes recognized in OCI 168 (186) (136)
Ending balance $ (779) $ (947) $ (761)
Weighted Average Assumptions Used to Determine Net Periodic Benefit Expense (Income)      
Discount rate 3.46% 4.01% 4.27%
Expected long-term rate of return on plan assets 3.50% 3.52% 3.61%
Rate of future compensation increases 3.38% 3.10% 3.19%
Other Postretirement Plan      
Components of Net Periodic Benefit Expense (Income)      
Service cost, benefits earned during the period $ 1 $ 1 $ 1
Interest cost on projected benefit obligation 3 3 4
Net amortization of prior service credit (1) (16) (17)
Net periodic benefit expense (income) 3 (12) (12)
Amounts Recognized in Other Comprehensive Loss (Income) on Pre-tax Basis      
Beginning balance 1 17 36
Net gain (loss) 13 0 (2)
Amortization of prior service credit (1) (16) (17)
Changes recognized in OCI 12 (16) (19)
Ending balance $ 13 $ 1 $ 17
Weighted Average Assumptions Used to Determine Net Periodic Benefit Expense (Income)      
Discount rate 3.44% 4.01% 4.13%