Pension and Other Employee Benefits (Pension Benefits Expected to be Paid from Plans or Companies Assets) (Details) $ in Millions	Dec. 31, 2019 USD ($)
Pension Plan [Member]
Defined Benefit Plans and PRB Plans [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 1,984
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	1,874
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	1,806
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	1,646
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	1,583
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	7,641
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	58
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	55
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	53
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	50
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	$ 218