Supplemental Schedule of Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums, Life Insurance in Force	$ 1,027.0	$ 1,117.0	$ 1,990.0
Ceded Premiums, Life Insurance in Force	151,569.0	166,842.0	184,625.0
Assumed Premiums, Life Insurance in Force	3,400,735.0	3,467,054.0	3,480,692.0
Premiums, Net, Life Insurance in Force	$ 3,250,193.0	$ 3,301,329.0	$ 3,298,057.0
Life Insurance in Force Premiums, Percentage Assumed to Net	104.60%	105.00%	105.50%
Direct Premiums Earned	$ 26.0	$ 33.0	$ 58.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	771.0	868.0	947.0
Assumed Premiums Earned	13,823.0	13,348.0	12,583.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 13,078.0	$ 12,513.0	$ 11,694.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	105.70%	106.70%	107.60%
US Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 25.0	$ 26.0	$ 23.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	421.0	472.0	585.0
Assumed Premiums Earned	6,986.0	6,690.0	6,399.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 6,590.0	$ 6,244.0	$ 5,837.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	106.00%	107.10%	109.60%
US Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 1.0	$ 2.0	$ 3.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0.0	0.0	0.0
Assumed Premiums Earned	65.0	53.0	50.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 66.0	$ 55.0	$ 53.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	98.50%	96.40%	94.30%
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	64.0	50.0	54.0
Assumed Premiums Earned	1,283.0	1,244.0	1,106.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,219.0	$ 1,194.0	$ 1,052.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	105.30%	104.20%	105.10%
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	95.0	90.0	83.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 95.0	$ 90.0	$ 83.0
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	$ 0.0	$ 5.0	$ 32.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	32.0	32.0	24.0
Assumed Premiums Earned	1,768.0	1,765.0	1,548.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,736.0	$ 1,738.0	$ 1,556.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	101.80%	101.60%	99.50%
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	137.0	202.0	178.0
Assumed Premiums Earned	623.0	552.0	430.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 486.0	$ 350.0	$ 252.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	128.20%	157.70%	170.60%
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	117.0	112.0	106.0
Assumed Premiums Earned	2,767.0	2,736.0	2,787.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 2,650.0	$ 2,624.0	$ 2,681.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	104.40%	104.30%	104.00%
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	236.0	218.0	180.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 236.0	$ 218.0	$ 180.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%