Supplemental Schedule of Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums, Life Insurance in Force	$ 863.0	$ 924.0	$ 1,027.0
Ceded Premiums, Life Insurance in Force	71,887.0	69,242.0	151,569.0
Assumed Premiums, Life Insurance in Force	3,878,640.0	3,704,061.0	3,400,735.0
Premiums, Net, Life Insurance in Force	$ 3,807,616.0	$ 3,635,743.0	$ 3,250,193.0
Life Insurance in Force Premiums, Percentage Assumed to Net	101.90%	101.90%	104.60%
Direct Premiums Earned	$ 2,919.0	$ 1,477.0	$ 26.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	649.0	673.0	778.0
Assumed Premiums Earned	15,573.0	14,281.0	13,830.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 17,843.0	$ 15,085.0	$ 13,078.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	87.30%	94.70%	105.80%
Life Insurance Product Line [Member] | Americas [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 14.0	$ 29.0	$ 25.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	175.0	195.0	421.0
Assumed Premiums Earned	7,661.0	7,189.0	6,986.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 7,500.0	$ 7,023.0	$ 6,590.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	102.10%	102.40%	106.00%
Life Insurance Product Line [Member] | CANADA
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	70.0	62.0	71.0
Assumed Premiums Earned	1,361.0	1,277.0	1,290.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,291.0	$ 1,215.0	$ 1,219.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	105.40%	105.10%	105.80%
Life Insurance Product Line [Member] | EMEA [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	24.0	30.0	32.0
Assumed Premiums Earned	2,026.0	1,805.0	1,768.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 2,002.0	$ 1,775.0	$ 1,736.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	101.20%	101.70%	101.80%
Life Insurance Product Line [Member] | Asia Pacific [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	93.0	137.0	117.0
Assumed Premiums Earned	3,107.0	2,922.0	2,767.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 3,014.0	$ 2,785.0	$ 2,650.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	103.10%	104.90%	104.40%
Insurance, Other [Member] | Americas [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 2,905.0	$ 1,448.0	$ 1.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	20.0	3.0	0.0
Assumed Premiums Earned	101.0	76.0	65.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 2,986.0	$ 1,521.0	$ 66.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	3.40%	5.00%	98.50%
Insurance, Other [Member] | CANADA
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	166.0	90.0	95.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 166.0	$ 90.0	$ 95.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%
Insurance, Other [Member] | EMEA [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	267.0	246.0	137.0
Assumed Premiums Earned	927.0	704.0	623.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 660.0	$ 458.0	$ 486.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	140.50%	153.70%	128.20%
Insurance, Other [Member] | Asia Pacific [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	224.0	218.0	236.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 224.0	$ 218.0	$ 236.0
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%