Managed Investment Entities - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) collateralizedloanobligation	Dec. 31, 2017 USD ($) collateralizedloanobligation	Dec. 31, 2016 USD ($) collateralizedloanobligation
Variable Interest Entity [Line Items]
Percentage of investment of most subordinate debt tranche, Minimum	15.00%
Percentage of investment of most subordinate debt tranche, Maximum	60.90%
Number of collateralized loan obligation entities | collateralizedloanobligation	15
Number of collateralized loan obligation entities formed during the period | collateralizedloanobligation	1	2	2
Face amount of managed investment entities liabilities purchased by subsidiaries after issuance date	$ 7	$ 71	$ 24
Amount paid by subsidiaries to purchase managed investment entities liabilities after issuance date	7	71	17
Proceeds received by subsidiaries related to sales and redemptions of managed investment entities liabilities	$ 45	$ 103	115
Number of collateralized loan obligation entities that were substantially liquidated during the period | collateralizedloanobligation	1	2
Difference between aggregate unpaid principal balance and fair value of CLOs' fixed maturity investments	$ 232	$ 55
Difference between aggregate unpaid principal balance and fair value of CLOs' debt	241	118
Carrying amount of CLO loans in default		1
Aggregate unpaid principal balance of CLO loans in default	0	8
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	188	215	216
New collateralized loan obligation entities
Variable Interest Entity [Line Items]
Face value of liabilities issued by managed investment entities on issuance date	463	865	866
Face amount of managed investment entities liabilities purchased by subsidiaries at issuance date	31	$ 48	$ 64
Subordinated debt obligations | Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	$ 125