Fair Value Measurements (excluding Consolidated Investment Entities) - Fair Value Measurement (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	$ 39,663.0	$ 36,897.0
Derivatives	316.0	194.0
Assets held in separate accounts	81,670.0	69,931.0
Total assets	169,051.0	155,430.0
Derivatives	403.0	164.0
Total liabilities	158,821.0	146,425.0
Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	43,778.0	40,592.0
U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,382.0	1,423.0
U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	95.0	74.0
State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,323.0	1,250.0
U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	14,938.0	14,876.0
U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	6,035.0	5,491.0
Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,341.0	4,135.0
Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,831.0	4,640.0
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	5,204.0	4,282.0
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	3,574.0	2,763.0
Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	2,055.0	1,658.0
Assets measured on recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	43,778.0	40,592.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	2,644.0	2,656.0
Assets held in separate accounts	81,670.0	69,931.0
Total assets	$ 128,604.0	$ 113,620.0
Percentage of Level to total	100.00%	100.00%
Total liabilities	$ 563.0	$ 203.0
Assets measured on recurring basis | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	60.0	44.0
Assets measured on recurring basis | Credit contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	2.0	3.0
Assets measured on recurring basis | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	294.0	179.0
Derivatives	371.0	137.0
Assets measured on recurring basis | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	12.0	13.0
Derivatives	22.0	22.0
Assets measured on recurring basis | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	10.0	2.0
Derivatives	8.0	2.0
Assets measured on recurring basis | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	100.0	(5.0)
Assets measured on recurring basis | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,382.0	1,423.0
Assets measured on recurring basis | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	95.0	74.0
Assets measured on recurring basis | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,323.0	1,250.0
Assets measured on recurring basis | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	14,938.0	14,876.0
Assets measured on recurring basis | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	6,035.0	5,491.0
Assets measured on recurring basis | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,341.0	4,135.0
Assets measured on recurring basis | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,831.0	4,640.0
Assets measured on recurring basis | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	5,204.0	4,282.0
Assets measured on recurring basis | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	3,574.0	2,763.0
Assets measured on recurring basis | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	2,055.0	1,658.0
Assets measured on recurring basis | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	196.0	247.0
Assets measured on recurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,083.0	1,236.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	2,613.0	2,628.0
Assets held in separate accounts	75,405.0	64,064.0
Total assets	$ 79,171.0	$ 68,072.0
Percentage of Level to total	61.00%	60.00%
Total liabilities	$ 0.0	$ 2.0
Assets measured on recurring basis | Level 1 | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	0.0	0.0
Assets measured on recurring basis | Level 1 | Credit contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 1 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	2.0	0.0
Derivatives	0.0	1.0
Assets measured on recurring basis | Level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 1 | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	1.0
Assets measured on recurring basis | Level 1 | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 1 | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,083.0	1,236.0
Assets measured on recurring basis | Level 1 | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	68.0	144.0
Assets measured on recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	40,735.0	37,802.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	31.0	28.0
Assets held in separate accounts	6,149.0	5,805.0
Total assets	$ 47,180.0	$ 43,790.0
Percentage of Level to total	37.00%	38.00%
Total liabilities	$ 454.0	$ 118.0
Assets measured on recurring basis | Level 2 | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	0.0	0.0
Assets measured on recurring basis | Level 2 | Credit contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	2.0	3.0
Assets measured on recurring basis | Level 2 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	243.0	140.0
Derivatives	322.0	97.0
Assets measured on recurring basis | Level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	12.0	13.0
Derivatives	22.0	22.0
Assets measured on recurring basis | Level 2 | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	10.0	2.0
Derivatives	8.0	1.0
Assets measured on recurring basis | Level 2 | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	100.0	(5.0)
Assets measured on recurring basis | Level 2 | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	299.0	187.0
Assets measured on recurring basis | Level 2 | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	95.0	74.0
Assets measured on recurring basis | Level 2 | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,323.0	1,250.0
Assets measured on recurring basis | Level 2 | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	14,864.0	14,842.0
Assets measured on recurring basis | Level 2 | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,578.0	4,357.0
Assets measured on recurring basis | Level 2 | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,341.0	4,135.0
Assets measured on recurring basis | Level 2 | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	4,503.0	4,423.0
Assets measured on recurring basis | Level 2 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	5,181.0	4,254.0
Assets measured on recurring basis | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	3,574.0	2,749.0
Assets measured on recurring basis | Level 2 | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,977.0	1,531.0
Assets measured on recurring basis | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0.0	0.0
Assets measured on recurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,960.0	1,554.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	0.0	0.0
Assets held in separate accounts	116.0	62.0
Total assets	$ 2,253.0	$ 1,758.0
Percentage of Level to total	2.00%	2.00%
Total liabilities	$ 109.0	$ 83.0
Assets measured on recurring basis | Level 3 | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	60.0	44.0
Assets measured on recurring basis | Level 3 | Credit contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 3 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	49.0	39.0
Derivatives	49.0	39.0
Assets measured on recurring basis | Level 3 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 3 | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 3 | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Assets measured on recurring basis | Level 3 | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 3 | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 3 | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 3 | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	74.0	34.0
Assets measured on recurring basis | Level 3 | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,457.0	1,134.0
Assets measured on recurring basis | Level 3 | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Assets measured on recurring basis | Level 3 | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	328.0	217.0
Assets measured on recurring basis | Level 3 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	23.0	28.0
Assets measured on recurring basis | Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	14.0
Assets measured on recurring basis | Level 3 | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	78.0	127.0
Assets measured on recurring basis | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	128.0	103.0
Held for sale | Assets measured on recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	593.0	10,529.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	533.0	734.0
Assets held in separate accounts	1,485.0	1,297.0
Total assets	$ 14,827.0	$ 12,716.0
Percentage of Level to total	100.00%	100.00%
Total liabilities	$ 369.0	$ 161.0
Held for sale | Assets measured on recurring basis | IUL
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	217.0	82.0
Held for sale | Assets measured on recurring basis | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	49.0	39.0
Derivatives	56.0	51.0
Held for sale | Assets measured on recurring basis | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	1.0	1.0
Derivatives	1.0	0.0
Held for sale | Assets measured on recurring basis | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	254.0	91.0
Derivatives	20.0	2.0
Held for sale | Assets measured on recurring basis | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	75.0	26.0
Held for sale | Assets measured on recurring basis | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	786.0	873.0
Held for sale | Assets measured on recurring basis | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	161.0	167.0
Held for sale | Assets measured on recurring basis | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	439.0	408.0
Held for sale | Assets measured on recurring basis | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	5,981.0	4,972.0
Held for sale | Assets measured on recurring basis | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	912.0	741.0
Held for sale | Assets measured on recurring basis | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,497.0	1,321.0
Held for sale | Assets measured on recurring basis | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	518.0	455.0
Held for sale | Assets measured on recurring basis | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged		521.0
Held for sale | Assets measured on recurring basis | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	588.0	653.0
Held for sale | Assets measured on recurring basis | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	995.0	418.0
Held for sale | Assets measured on recurring basis | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	12,470.0
Equity securities	35.0	25.0
Held for sale | Assets measured on recurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	472.0	518.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	533.0	734.0
Assets held in separate accounts	1,485.0	1,297.0
Total assets	$ 2,492.0	$ 2,549.0
Percentage of Level to total	17.00%	20.00%
Total liabilities	$ 0.0	$ 0.0
Held for sale | Assets measured on recurring basis | Level 1 | IUL
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	472.0	518.0
Held for sale | Assets measured on recurring basis | Level 1 | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2.0	0.0
Held for sale | Assets measured on recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	11,557.0	9,686.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	0.0	0.0
Assets held in separate accounts	0.0	0.0
Total assets	$ 11,610.0	$ 9,695.0
Percentage of Level to total	78.00%	76.00%
Total liabilities	$ 103.0	$ 40.0
Held for sale | Assets measured on recurring basis | Level 2 | IUL
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 2 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	7.0	12.0
Held for sale | Assets measured on recurring basis | Level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	1.0	1.0
Derivatives	1.0	0.0
Held for sale | Assets measured on recurring basis | Level 2 | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	52.0	8.0
Derivatives	20.0	2.0
Held for sale | Assets measured on recurring basis | Level 2 | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	75.0	26.0
Held for sale | Assets measured on recurring basis | Level 2 | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	314.0	355.0
Held for sale | Assets measured on recurring basis | Level 2 | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	161.0	167.0
Held for sale | Assets measured on recurring basis | Level 2 | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	439.0	408.0
Held for sale | Assets measured on recurring basis | Level 2 | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	5,949.0	4,962.0
Held for sale | Assets measured on recurring basis | Level 2 | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	596.0	482.0
Held for sale | Assets measured on recurring basis | Level 2 | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	1,490.0	1,310.0
Held for sale | Assets measured on recurring basis | Level 2 | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	438.0	421.0
Held for sale | Assets measured on recurring basis | Level 2 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	588.0	521.0
Held for sale | Assets measured on recurring basis | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	995.0	653.0
Held for sale | Assets measured on recurring basis | Level 2 | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	587.0	407.0
Held for sale | Assets measured on recurring basis | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	441.0	325.0
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	0.0	0.0
Assets held in separate accounts	0.0	0.0
Total assets	$ 725.0	$ 472.0
Percentage of Level to total	5.00%	4.00%
Total liabilities	$ 266.0	$ 121.0
Held for sale | Assets measured on recurring basis | Level 3 | IUL
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives:	217.0	82.0
Held for sale | Assets measured on recurring basis | Level 3 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	49.0	39.0
Derivatives	49.0	39.0
Held for sale | Assets measured on recurring basis | Level 3 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	202.0	83.0
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | U.S. Government agencies and authorities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | State, municipalities, and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | U.S. corporate public securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	32.0	10.0
Held for sale | Assets measured on recurring basis | Level 3 | U.S. corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	316.0	259.0
Held for sale | Assets measured on recurring basis | Level 3 | Foreign corporate public securities and foreign governments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	7.0	11.0
Held for sale | Assets measured on recurring basis | Level 3 | Foreign corporate private securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	80.0	34.0
Held for sale | Assets measured on recurring basis | Level 3 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	0.0	0.0
Held for sale | Assets measured on recurring basis | Level 3 | Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	6.0	11.0
Held for sale | Assets measured on recurring basis | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 33.0	$ 25.0