Equity (Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	[1]	Jan. 01, 2018	Jan. 01, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 10,906
Income tax benefit (expense)	(3,811)	$ 1,812	$ (784)
Cumulative effect of adoption		9		$ (14)			$ 0
Ending balance	24,039	10,906
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(564)	(269)	(973)
Change in OCI before reclassifications	37	(74)	768
Amounts reclassified from AOCI	27	1	1
Income tax benefit (expense)	(36)	9	(65)
Ending balance	(536)	(564)	(269)
Net Unrealized Investment Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	14,745	19,968	18,171
Change in OCI before reclassifications	18,540	(7,614)	4,026
Amounts reclassified from AOCI	(1,345)	(779)	(1,629)
Income tax benefit (expense)	(3,835)	1,735	(600)
Ending balance	28,112	14,745	19,968
Pension and Postretirement Unrecognized Net Periodic Benefit (Cost)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(3,275)	(2,625)	(2,577)
Change in OCI before reclassifications	(563)	(547)	(153)
Amounts reclassified from AOCI	241	227	224
Income tax benefit (expense)	60	68	(119)
Ending balance	(3,537)	(3,275)	(2,625)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	10,906	17,074	14,621
Change in OCI before reclassifications	18,014	(8,235)	4,641
Amounts reclassified from AOCI	(1,077)	(551)	(1,404)
Income tax benefit (expense)	(3,811)	1,812	(784)
Cumulative effect of adoption				$ 7		$ 1,653
Ending balance	24,039	10,906	17,074
Cash flow hedges | Net Unrealized Investment Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	811	(39)
Ending balance	832	811	$ (39)
ASU 2016-01
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption						57
ASU 2016-01 | Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		0
ASU 2016-01 | Net Unrealized Investment Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		(847)
ASU 2016-01 | Pension and Postretirement Unrecognized Net Periodic Benefit (Cost)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		0
ASU 2016-01 | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		(847)				$ (847)
ASU 2018-02 | Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		(231)
ASU 2018-02 | Net Unrealized Investment Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		2,282
ASU 2018-02 | Pension and Postretirement Unrecognized Net Periodic Benefit (Cost)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		(398)
ASU 2018-02 | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption		$ 1,653
ASU 2017-12 | Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption	0
ASU 2017-12 | Net Unrealized Investment Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption	7
ASU 2017-12 | Pension and Postretirement Unrecognized Net Periodic Benefit (Cost)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption	0
ASU 2017-12 | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative effect of adoption	$ 7

[1] Includes the impact from the adoption of ASU 2017-08 and 2017-12. See Note 2.