Employee Benefit Plans (Actual & Target Allocation of Fair Value by Asset Class) (Details) - U.S.	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Actual	100.00%	100.00%
Pension Benefits | Fixed Maturity Securities
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Target	82.00%
Actual	81.00%	82.00%
Pension Benefits | Equity securities
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Target	15.00%
Actual	12.00%	10.00%
Pension Benefits | Alternative Securities
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Target	3.00%
Actual	7.00%	8.00%
Other Postretirement Benefits
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Actual	100.00%	100.00%
Other Postretirement Benefits | Fixed Maturity Securities
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Target	95.00%
Actual	95.00%	82.00%
Other Postretirement Benefits | Equity securities
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Target	5.00%
Actual	5.00%	18.00%
Other Postretirement Benefits | Alternative Securities
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]
Target	0.00%
Actual	0.00%	0.00%