Pension and Other Employee Benefits (Pension Benefits Expected to be Paid from Plans or Companies Assets) (Details)
$ in Millions |
Dec. 31, 2018
USD ($)
|
| Pension Plan [Member] |
|
| Defined Benefit Plans and PRB Plans [Line Items] |
|
| Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months |
$ 2,008
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Two |
1,878
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Three |
1,818
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Four |
1,744
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Five |
1,599
|
| Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter |
7,612
|
| PRB [Member] |
|
| Defined Benefit Plans and PRB Plans [Line Items] |
|
| Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months |
61
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Two |
60
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Three |
58
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Four |
55
|
| Defined Benefit Plan, Expected Future Benefit Payment, Year Five |
53
|
| Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter |
$ 231
|