Reinsurance - Reinsurance Recoverables by Range of External Credit Rating and Collateral Level (Details) $ in Millions	Mar. 31, 2020 USD ($)
Ceded Credit Risk [Line Items]
Reinsurance recoverables	$ 5,494
Allowance for uncollectible reinsurance	(34)
Reinsurance recoverables classified as assets of business held for sale	(175)
Total reinsurance recoverables	5,285
Fair value of collateral contractually required to meet or exceed carrying value of recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverables	1,364
Collateral provisions exist that may mitigate risk of credit loss
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,711
No collateral
Ceded Credit Risk [Line Items]
Reinsurance recoverables	419
Ongoing Operations
Ceded Credit Risk [Line Items]
Reinsurance recoverables	504
Ongoing Operations | Upper-medium grade and higher
Ceded Credit Risk [Line Items]
Reinsurance recoverables	316
Ongoing Operations | Lower-medium grade
Ceded Credit Risk [Line Items]
Reinsurance recoverables	63
Ongoing Operations | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	125
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverables	87
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Upper-medium grade and higher
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Lower-medium grade
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	87
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss
Ceded Credit Risk [Line Items]
Reinsurance recoverables	21
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss | Upper-medium grade and higher
Ceded Credit Risk [Line Items]
Reinsurance recoverables	6
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss | Lower-medium grade
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	15
Ongoing Operations | No collateral
Ceded Credit Risk [Line Items]
Reinsurance recoverables	396
Ongoing Operations | No collateral | Upper-medium grade and higher
Ceded Credit Risk [Line Items]
Reinsurance recoverables	310
Ongoing Operations | No collateral | Lower-medium grade
Ceded Credit Risk [Line Items]
Reinsurance recoverables	63
Ongoing Operations | No collateral | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	23
Acquisition, disposition or runoff activities
Ceded Credit Risk [Line Items]
Reinsurance recoverables	4,990
Acquisition, disposition or runoff activities | Upper-medium grade and higher | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,137
Acquisition, disposition or runoff activities | Upper-medium grade and higher | Berkshire
Ceded Credit Risk [Line Items]
Reinsurance recoverables	829
Acquisition, disposition or runoff activities | Upper-medium grade and higher | Prudential Retirement Insurance and Annuity
Ceded Credit Risk [Line Items]
Reinsurance recoverables	692
Acquisition, disposition or runoff activities | Upper-medium grade and higher | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	288
Acquisition, disposition or runoff activities | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	44
Acquisition, disposition or runoff activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverables	1,277
Acquisition, disposition or runoff activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Upper-medium grade and higher | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or runoff activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Upper-medium grade and higher | Berkshire
Ceded Credit Risk [Line Items]
Reinsurance recoverables	337
Acquisition, disposition or runoff activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Upper-medium grade and higher | Prudential Retirement Insurance and Annuity
Ceded Credit Risk [Line Items]
Reinsurance recoverables	692
Acquisition, disposition or runoff activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Upper-medium grade and higher | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	248
Acquisition, disposition or runoff activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or runoff activities | Collateral provisions exist that may mitigate risk of credit loss
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,690
Acquisition, disposition or runoff activities | Collateral provisions exist that may mitigate risk of credit loss | Upper-medium grade and higher | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,137
Acquisition, disposition or runoff activities | Collateral provisions exist that may mitigate risk of credit loss | Upper-medium grade and higher | Berkshire
Ceded Credit Risk [Line Items]
Reinsurance recoverables	492
Acquisition, disposition or runoff activities | Collateral provisions exist that may mitigate risk of credit loss | Upper-medium grade and higher | Prudential Retirement Insurance and Annuity
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or runoff activities | Collateral provisions exist that may mitigate risk of credit loss | Upper-medium grade and higher | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	21
Acquisition, disposition or runoff activities | Collateral provisions exist that may mitigate risk of credit loss | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	40
Acquisition, disposition or runoff activities | No collateral
Ceded Credit Risk [Line Items]
Reinsurance recoverables	23
Acquisition, disposition or runoff activities | No collateral | Upper-medium grade and higher | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or runoff activities | No collateral | Upper-medium grade and higher | Berkshire
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or runoff activities | No collateral | Upper-medium grade and higher | Prudential Retirement Insurance and Annuity
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or runoff activities | No collateral | Upper-medium grade and higher | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	19
Acquisition, disposition or runoff activities | No collateral | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	$ 4