Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (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, available-for-sale:	[1]	$ 391,096	$ 353,656
Assets supporting experience-rated contractholder liabilities	[1]	21,597	21,254
Fixed maturities, trading	[1]	3,884	3,243
Equity securities	[1]	7,522	6,238
Commercial mortgage and other loans	[1]	63,559	59,830
Other invested assets	[1]	15,606	14,526
Short-term investments		5,467
Other assets	[1]	20,832	16,118
Separate account assets		312,281	279,136
TOTAL ASSETS		896,552	815,078
Future policy benefits		293,527	273,846
Other liabilities	[1]	20,802	16,018
Total liabilities		832,833	766,047
Netting		(13,519)	(9,331)
Embedded Derivative, Fair Value of Embedded Derivative, Net Liability		14,035	8,959
Future policy benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative, Net Liability		12,800	8,900
Embedded Derivative, Fair Value of Embedded Derivative Gross Asset		700	700
Embedded Derivative, Fair Value of Embedded Derivative Gross Liability		13,500	9,600
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		391,096	353,656
Assets supporting experience-rated contractholder liabilities		21,581	21,254
Fixed maturities, trading		3,884	3,243
Equity securities		7,385	6,100
Commercial mortgage and other loans		228	763
Other invested assets		1,433	1,409
Short-term investments		3,936	5,493
Cash equivalents		9,006	9,478
Other assets		113	25
Separate account assets		288,724	254,066
TOTAL ASSETS		727,386	655,487
Future policy benefits		12,831	8,926
Policyholders' account balances		1,316	56
Other liabilities		936	135
Notes issued by consolidated VIEs		800	595
Total liabilities		15,883	9,712
Asset Netting		(13,519)	(9,331)
Liability Netting		(6,705)	(5,281)
Netting		(6,814)	(4,050)
Fair Value, Measurements, Recurring | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Netting		(13,519)	(9,331)
Fair Value, Measurements, Recurring | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability Netting		(6,705)	(5,281)
Fair Value, Measurements, Recurring | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		35,659	30,594
Assets supporting experience-rated contractholder liabilities		185	381
Fair Value, Measurements, Recurring | Obligations of U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		11,497	10,493
Assets supporting experience-rated contractholder liabilities		212	196
Fair Value, Measurements, Recurring | Foreign government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		119,054	113,110
Assets supporting experience-rated contractholder liabilities		814	1,083
Fair Value, Measurements, Recurring | U.S. public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		98,339	83,415
Fair Value, Measurements, Recurring | U.S. private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		36,533	33,020
Fair Value, Measurements, Recurring | Foreign public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		29,825	29,201
Fair Value, Measurements, Recurring | Foreign private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		28,240	24,531
Fair Value, Measurements, Recurring | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		13,603	13,119
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		13,174	12,973
Assets supporting experience-rated contractholder liabilities		1,662	1,665
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		15,574	13,315
Assets supporting experience-rated contractholder liabilities		1,896	2,324
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		3,201	3,004
Assets supporting experience-rated contractholder liabilities		1,158	811
Fair Value, Measurements, Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		1,790	1,460
Fair Value, Measurements, Recurring | All other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		261	215
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		1,505	1,222
Fixed maturities, trading		0	0
Equity securities		5,813	4,819
Commercial mortgage and other loans		0	0
Other invested assets		6	23
Short-term investments		1,806	2,713
Cash equivalents		2,079	2,848
Other assets		0	0
Separate account assets		46,574	39,534
TOTAL ASSETS		57,783	51,159
Future policy benefits		0	0
Policyholders' account balances		0	0
Other liabilities		41	18
Notes issued by consolidated VIEs		0	0
Total liabilities		41	18
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Obligations of U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Fair Value, Measurements, Recurring | Level 1 | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	0
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		1,505	1,222
Fair Value, Measurements, Recurring | Level 1 | All other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		386,781	349,421
Assets supporting experience-rated contractholder liabilities		19,346	19,213
Fixed maturities, trading		3,597	3,037
Equity securities		939	610
Commercial mortgage and other loans		228	763
Other invested assets		14,379	10,454
Short-term investments		1,975	2,691
Cash equivalents		6,796	6,553
Other assets		0	0
Separate account assets		240,433	212,998
TOTAL ASSETS		674,474	605,740
Future policy benefits		0	0
Policyholders' account balances		0	0
Other liabilities		7,495	5,398
Notes issued by consolidated VIEs		0	0
Total liabilities		7,495	5,398
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		35,554	30,513
Assets supporting experience-rated contractholder liabilities		185	381
Fair Value, Measurements, Recurring | Level 2 | Obligations of U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		11,493	10,488
Assets supporting experience-rated contractholder liabilities		212	196
Fair Value, Measurements, Recurring | Level 2 | Foreign government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		119,032	112,985
Assets supporting experience-rated contractholder liabilities		790	858
Fair Value, Measurements, Recurring | Level 2 | U.S. public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		97,959	83,282
Fair Value, Measurements, Recurring | Level 2 | U.S. private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		34,749	31,265
Fair Value, Measurements, Recurring | Level 2 | Foreign public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		29,756	29,148
Fair Value, Measurements, Recurring | Level 2 | Foreign private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		27,237	23,787
Fair Value, Measurements, Recurring | Level 2 | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		12,966	12,675
Fair Value, Measurements, Recurring | Level 2 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		12,238	11,726
Assets supporting experience-rated contractholder liabilities		1,593	1,516
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		15,574	13,302
Assets supporting experience-rated contractholder liabilities		1,896	2,324
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		3,189	2,925
Assets supporting experience-rated contractholder liabilities		1,158	811
Fair Value, Measurements, Recurring | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		285	237
Fair Value, Measurements, Recurring | Level 2 | All other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		261	215
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		4,315	4,235
Assets supporting experience-rated contractholder liabilities		730	819
Fixed maturities, trading		287	206
Equity securities		633	671
Commercial mortgage and other loans		0	0
Other invested assets		567	263
Short-term investments		155	89
Cash equivalents		131	77
Other assets		113	25
Separate account assets		1,717	1,534
TOTAL ASSETS		8,648	7,919
Future policy benefits		12,831	8,926
Policyholders' account balances		1,316	56
Other liabilities		105	0
Notes issued by consolidated VIEs		800	595
Total liabilities		15,052	9,577
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		105	81
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 3 | Obligations of U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		4	5
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 3 | Foreign government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		22	125
Assets supporting experience-rated contractholder liabilities		24	225
Fair Value, Measurements, Recurring | Level 3 | U.S. public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		380	133
Fair Value, Measurements, Recurring | Level 3 | U.S. private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		1,784	1,755
Fair Value, Measurements, Recurring | Level 3 | Foreign public corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		69	53
Fair Value, Measurements, Recurring | Level 3 | Foreign private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		1,003	744
Fair Value, Measurements, Recurring | Level 3 | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		637	444
Fair Value, Measurements, Recurring | Level 3 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		936	1,247
Assets supporting experience-rated contractholder liabilities		69	149
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		0	13
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		12	79
Assets supporting experience-rated contractholder liabilities		0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		0	1
Fair Value, Measurements, Recurring | Level 3 | All other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets supporting experience-rated contractholder liabilities		0	0
Prudential Netting Agreement | U.S. private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		4,751	4,216
Prudential Netting Agreement | Fair Value, Measurements, Recurring | U.S. private corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:		4,757	4,216
Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value investment measured at NAV per share		4,213	4,115
Separate account assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value investment measured at NAV per share		$ 23,557	$ 25,070

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