Investments (Fixed Maturities Securities Excluding Investments Classified as Trading) (Details) - USD ($) $ in Millions		Mar. 31, 2020		Dec. 31, 2019
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		$ 349,665		$ 346,574
Allowance for Credit Losses		158
Fair Value	[2]	389,714	[1]	391,096
Amortized Cost	[2]	1,895	[1]	1,933
Fair Value		2,249		2,302
Allowance for Credit Losses		9
Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		349,665		346,574
Gross Unrealized Gains		47,332		45,837
Gross Unrealized Losses		7,125		1,315
Allowance for Credit Losses		158
Fair Value		389,714		391,096
Amortized Cost		1,904		1,933
Gross Unrealized Gains		345		369
Gross Unrealized Losses		0		0
Fair Value		2,249		2,302
Allowance for Credit Losses		9
Amortized Cost, Net of Allowance		1,895
Fixed maturities | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		32,021		30,625
Gross Unrealized Gains		11,622		5,195
Gross Unrealized Losses		0		161
Allowance for Credit Losses		0
Fair Value		43,643		35,659
Fixed maturities | Obligations of U.S. states and their political subdivisions
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		10,111		10,068
Gross Unrealized Gains		1,399		1,437
Gross Unrealized Losses		21		8
Allowance for Credit Losses		0
Fair Value		11,489		11,497
Fixed maturities | Foreign government bonds
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		97,589		98,356
Gross Unrealized Gains		19,645		20,761
Gross Unrealized Losses		113		63
Allowance for Credit Losses		38
Fair Value		117,083		119,054
Amortized Cost		896		891
Gross Unrealized Gains		262		282
Gross Unrealized Losses		0		0
Fair Value		1,158		1,173
Allowance for Credit Losses		0
Amortized Cost, Net of Allowance		896
Fixed maturities | U.S. public corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		89,101		87,566
Gross Unrealized Gains		9,465		11,030
Gross Unrealized Losses		2,588		257
Allowance for Credit Losses		56
Fair Value		95,922		98,339
Fixed maturities | U.S. private corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		34,765		34,410
Gross Unrealized Gains		1,489		2,243
Gross Unrealized Losses		772		120
Allowance for Credit Losses		37
Fair Value		35,445		36,533
Fixed maturities | Foreign public corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		26,308		26,841
Gross Unrealized Gains		2,395		3,054
Gross Unrealized Losses		701		70
Allowance for Credit Losses		26
Fair Value		27,976		29,825
Amortized Cost		624		649
Gross Unrealized Gains		58		64
Gross Unrealized Losses		0		0
Fair Value		682		713
Allowance for Credit Losses		9
Amortized Cost, Net of Allowance		615
Fixed maturities | Foreign private corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		27,765		27,619
Gross Unrealized Gains		359		1,201
Gross Unrealized Losses		2,313		580
Allowance for Credit Losses		0
Fair Value		25,811		28,240
Amortized Cost		83		83
Gross Unrealized Gains		2		2
Gross Unrealized Losses		0		0
Fair Value		85		85
Allowance for Credit Losses		0
Amortized Cost, Net of Allowance		83
Fixed maturities | Asset-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		13,859		13,067
Gross Unrealized Gains		98		147
Gross Unrealized Losses		577		40
Allowance for Credit Losses		0
Fair Value		13,380		13,174
Fixed maturities | Commercial mortgage-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		14,951		14,978
Gross Unrealized Gains		653		610
Gross Unrealized Losses		31		14
Allowance for Credit Losses		1
Fair Value		15,572		15,574
Fixed maturities | Residential mortgage-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		3,195		3,044
Gross Unrealized Gains		207		159
Gross Unrealized Losses		9		2
Allowance for Credit Losses		0
Fair Value		3,393		3,201
Amortized Cost		301		310
Gross Unrealized Gains		23		21
Gross Unrealized Losses		0		0
Fair Value		324		331
Allowance for Credit Losses		0
Amortized Cost, Net of Allowance		301
Available-for-sale | OTTI | Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				(119)
Available-for-sale | OTTI | Fixed maturities | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				0
Available-for-sale | OTTI | Fixed maturities | Obligations of U.S. states and their political subdivisions
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				0
Available-for-sale | OTTI | Fixed maturities | Foreign government bonds
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				(34)
Available-for-sale | OTTI | Fixed maturities | U.S. public corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				(6)
Available-for-sale | OTTI | Fixed maturities | U.S. private corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				0
Available-for-sale | OTTI | Fixed maturities | Foreign public corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				(1)
Available-for-sale | OTTI | Fixed maturities | Foreign private corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				0
Available-for-sale | OTTI | Fixed maturities | Asset-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				(77)
Available-for-sale | OTTI | Fixed maturities | Commercial mortgage-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				0
Available-for-sale | OTTI | Fixed maturities | Residential mortgage-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				(1)
Available-for-sale | Net Unrealized Investment Gains (Losses) | Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				362
Held-to-maturity | Net Unrealized Investment Gains (Losses) | Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
OTTI in AOCI				1
Prudential Netting Agreement | U.S. private corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fair Value		5,616		4,751
Prudential Netting Agreement | Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		4,998		4,998
Fair Value		5,001		5,401
Prudential Netting Agreement | Fixed maturities | U.S. private corporate securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Amortized Cost		5,616		4,751
Fair Value		$ 5,616		$ 4,757

[1] March 31, 2020 amounts include the impacts of the January 1, 2020 adoption of ASU 2016-13. See Note 2 for details.

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