Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 13,052	$ 1,722
OCI before reclassifications	(606)	6,675
Deferred income tax benefit (expense)	91	(1,516)
AOCI before reclassifications, net of income tax	12,537	6,881
Amounts reclassified from AOCI	272	3
Deferred income tax benefit (expense)	(52)	6
Amounts reclassified from AOCI, net of income tax	220	9
Balance, end of period	12,757	6,911
Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	18,283	7,042
OCI before reclassifications	(3,619)	6,721
Deferred income tax benefit (expense)	927	(1,516)
AOCI before reclassifications, net of income tax	15,591	12,247
Amounts reclassified from AOCI	(187)	(2)
Deferred income tax benefit (expense)	48	0
Amounts reclassified from AOCI, net of income tax	(139)	(2)
Balance, end of period	15,452	12,248
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	1,698	1,613
OCI before reclassifications	3,687	(11)
Deferred income tax benefit (expense)	(810)	6
AOCI before reclassifications, net of income tax	4,575	1,608
Amounts reclassified from AOCI	438	(24)
Deferred income tax benefit (expense)	(96)	12
Amounts reclassified from AOCI, net of income tax	342	(12)
Balance, end of period	4,917	1,614
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(4,927)	(4,905)
OCI before reclassifications	(674)	(36)
Deferred income tax benefit (expense)	(26)	(6)
AOCI before reclassifications, net of income tax	(5,627)	(4,947)
Amounts reclassified from AOCI	0	0
Deferred income tax benefit (expense)	0	0
Amounts reclassified from AOCI, net of income tax	0	0
Balance, end of period	(5,627)	(4,947)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(2,002)	(2,028)
OCI before reclassifications	0	1
Deferred income tax benefit (expense)	0	0
AOCI before reclassifications, net of income tax	(2,002)	(2,027)
Amounts reclassified from AOCI	21	29
Deferred income tax benefit (expense)	(4)	(6)
Amounts reclassified from AOCI, net of income tax	17	23
Balance, end of period	$ (1,985)	(2,004)
Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		26
Deferred income tax benefit (expense)		(5)
Amounts reclassified from AOCI, net of income tax		21
Accounting Standards Update 2017-12 | Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		4
Deferred income tax benefit (expense)		(1)
Amounts reclassified from AOCI, net of income tax		3
Accounting Standards Update 2017-12 | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		22
Deferred income tax benefit (expense)		(4)
Amounts reclassified from AOCI, net of income tax		18
Accounting Standards Update 2017-12 | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
Deferred income tax benefit (expense)		0
Amounts reclassified from AOCI, net of income tax		0
Accounting Standards Update 2017-12 | Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
Deferred income tax benefit (expense)		0
Amounts reclassified from AOCI, net of income tax		$ 0