Variable Interest Entities (Assets and Liabilities of Consolidated VIEs) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		$ 873,712	$ 896,552
Document Period End Date		Mar. 31, 2020
Total liabilities of consolidated VIEs		$ 812,640	832,833
Consolidated VIEs for Which the Company is the Investment Manager
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		5,141	5,048
Total liabilities of consolidated VIEs		1,633	1,578
Consolidated VIEs for Which the Company is the Investment Manager | Assets supporting experience-rated contractholder liabilities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		0	0
Consolidated VIEs for Which the Company is the Investment Manager | Equity securities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		39	47
Consolidated VIEs for Which the Company is the Investment Manager | Commercial mortgage and other loans
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		944	883
Consolidated VIEs for Which the Company is the Investment Manager | Other
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		2,222	2,199
Consolidated VIEs for Which the Company is the Investment Manager | Cash and cash equivalents
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		203	166
Consolidated VIEs for Which the Company is the Investment Manager | Accrued investment income
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		4	4
Consolidated VIEs for Which the Company is the Investment Manager | Other assets
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		426	450
Consolidated VIEs for Which the Company is the Investment Manager | Other liabilities
Variable Interest Entity [Line Items]
Total liabilities of consolidated VIEs		382	304
Consolidated VIEs for Which the Company is the Investment Manager | Notes Issued by Consolidated VIEs
Variable Interest Entity [Line Items]
Total liabilities of consolidated VIEs	[1]	1,251	1,274
Consolidated VIEs for Which the Company is the Investment Manager | Available-for-sale | Fixed maturities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		99	104
Consolidated VIEs for Which the Company is the Investment Manager | Held-to-maturity | Fixed maturities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		83	83
Consolidated VIEs for Which the Company is the Investment Manager | Trading | Fixed maturities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		1,121	1,112
Consolidated VIEs for Which the Company is the Investment Manager | ASU 2015-02, Wholly-owned by consolidated subsidiaries
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		2,663	2,668
Other Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		1,914	1,910
Total liabilities of consolidated VIEs		35	13
Other Consolidated VIEs | Assets supporting experience-rated contractholder liabilities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		3	4
Other Consolidated VIEs | Equity securities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		0	0
Other Consolidated VIEs | Commercial mortgage and other loans
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		0	0
Other Consolidated VIEs | Other
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		161	89
Other Consolidated VIEs | Cash and cash equivalents
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		0	0
Other Consolidated VIEs | Accrued investment income
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		4	4
Other Consolidated VIEs | Other assets
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		618	689
Other Consolidated VIEs | Other liabilities
Variable Interest Entity [Line Items]
Total liabilities of consolidated VIEs		35	13
Other Consolidated VIEs | Notes Issued by Consolidated VIEs
Variable Interest Entity [Line Items]
Total liabilities of consolidated VIEs		0	0
Other Consolidated VIEs | Available-for-sale | Fixed maturities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		284	285
Other Consolidated VIEs | Held-to-maturity | Fixed maturities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		844	839
Other Consolidated VIEs | Trading | Fixed maturities
Variable Interest Entity [Line Items]
Total assets of consolidated VIEs		$ 0	$ 0
Consolidated VIEs for Which the Company is the Investment Manager | Minimum | Notes Issued by Consolidated VIEs
Variable Interest Entity [Line Items]
VIEs Liabilities, maturities obligations (greater than)		4 years
Consolidated VIEs for Which the Company is the Investment Manager | Maximum | Notes Issued by Consolidated VIEs
Variable Interest Entity [Line Items]
VIEs Liabilities, maturities obligations (greater than)		9 years

[1] See Note 4 for details of balances associated with variable interest entities.