Supplemental Schedule of Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums, Life Insurance in Force	$ 1,117.0	$ 1,990.0	$ 1,316.0
Ceded Premiums, Life Insurance in Force	166,842.0	184,625.0	192,864.0
Assumed Premiums, Life Insurance in Force	3,467,054.0	3,480,692.0	3,480,206.0
Premiums, Net, Life Insurance in Force	$ 3,301,329.0	$ 3,298,057.0	$ 3,288,658.0
Life Insurance in Force Premiums, Percentage Assumed to Net	105.00%	105.50%	105.80%
Direct Premiums Earned	$ 33.0	$ 58.0	$ 76.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	868.0	947.0	929.0
Assumed Premiums Earned	13,348.0	12,583.0	12,150.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 12,513.0	$ 11,694.0	$ 11,297.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	106.70%	107.60%	107.50%
US Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 26.0	$ 23.0	$ 29.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	472.0	585.0	591.0
Assumed Premiums Earned	6,690.0	6,399.0	6,291.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 6,244.0	$ 5,837.0	$ 5,729.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	107.10%	109.60%	109.80%
US Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 2.0	$ 3.0	$ 2.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0.0	0.0	0.0
Assumed Premiums Earned	53.0	50.0	37.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 55.0	$ 53.0	$ 39.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	96.40%	94.30%	95.40%
Canada Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0.0	$ 0.0	$ 0.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	50.0	54.0	54.0
Assumed Premiums Earned	1,244.0	1,106.0	1,120.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,194.0	$ 1,052.0	$ 1,066.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	104.20%	105.10%	105.00%
Canada Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0.0	$ 0.0	$ 0.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0.0	0.0	0.0
Assumed Premiums Earned	90.0	83.0	89.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 90.0	$ 83.0	$ 89.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%
EMEA Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 5.0	$ 32.0	$ 45.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	32.0	24.0	52.0
Assumed Premiums Earned	1,765.0	1,548.0	1,449.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,738.0	$ 1,556.0	$ 1,442.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	101.60%	99.50%	100.60%
EMEA Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0.0	$ 0.0	$ 0.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	202.0	178.0	148.0
Assumed Premiums Earned	552.0	430.0	366.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 350.0	$ 252.0	$ 218.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	157.70%	170.60%	167.90%
Asia Pacific Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0.0	$ 0.0	$ 0.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	112.0	106.0	84.0
Assumed Premiums Earned	2,736.0	2,787.0	2,652.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 2,624.0	$ 2,681.0	$ 2,568.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	104.30%	104.00%	103.20%
Asia Pacific Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0.0	$ 0.0	$ 0.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0.0	0.0	0.0
Assumed Premiums Earned	218.0	180.0	146.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 218.0	$ 180.0	$ 146.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%