Shareholders' Equity - Progression of the components of accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			$ 1,273
Other comprehensive income (loss), pretax	$ (985)	$ 1,292	(1,371)	$ 245
Other comprehensive income (loss), tax	208	(271)	288	(53)
Other comprehensive income (loss), net of tax	(777)	1,021	(1,083)	192
Reclassify AOCI	190		190
AOCI ending balance	190		190
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, pretax	168	1,293	(187)	198
Unrealized holding gains (losses) on securities arising during the period, tax	(35)	(272)	39	(42)
Unrealized holding gains (losses) on securities arising during the period, after tax	(133)	(1,021)	148	(156)
Reclassification adjustment for realized (gains) losses included in net earnings, pretax	(9)	(9)	(23)	15
Reclassification adjustment for realized (gains) losses included in net earnings, tax	2	2	5	(3)
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	(7)	(7)	(18)	12
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, pretax	(1,119)		(1,119)
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, tax	235		235
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, after tax	(884)	0	(884)	0
Total net unrealized gains (losses) on securities, pretax	(960)	1,284	(1,329)	213
Total net unrealized gains (losses) on securities, tax	202	(270)	279	(45)
Total net unrealized gains (losses) on securities	(758)	1,014	(1,050)	168
Net unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) on cash flow hedges arising during the period, pretax	7	16	(1)	61
Unrealized holding gains (losses) on cash flow hedges arising during the period, tax	(1)	(4)	0	(13)
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax	6	12	(1)	48
Reclassification adjustment for investment income included in net earnings from discontinued operations, pretax	(5)	(12)	(14)	(23)
Reclassification adjustment for investment income included in net earnings from discontinued operations, tax	1	3	3	5
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax	(4)	(9)	(11)	(18)
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, pretax	(37)		(37)
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, tax	8		8
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, after tax	(29)	0	(29)	0
Total net unrealized gains (losses) on cash flow hedges, pretax	(35)	4	(52)	38
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	8	(1)	11	(8)
Total net unrealized gains (losses) on cash flow hedges	(27)	3	(41)	30
Foreign currency translation adjustments, pretax	0	4	0	(6)
Foreign currency translation adjustments, tax	0	0	0	0
Foreign currency translation adjustments	0	4	0	(6)
Pension and other postretirement plans (“OPRP”) adjustments:
Unrealized holding gains (losses) on pension and OPRP arising during the period, pretax	(1)		(1)
Unrealized holding gains (losses) on pension and OPRP arising during the period, tax	0		0
Unrealized holding gains (losses) on pension and OPRP arising during the period, after tax	(1)	0	(1)	0
Reclassification adjustment for pension settlement loss included in other expense in net earnings, pretax	11		11
Reclassification adjustment for pension settlement loss included in other expense in net earnings, tax	(2)		(2)
Reclassification adjustment for pension settlement loss included in net earnings	9	0	9	0
Total pension and OPRP adjustments, pretax	10	0	10	0
Total pension and OPRP adjustments, tax	(2)	0	(2)	0
Total pension and OPRP adjustments	8	0	8	0
Attributable to noncontrolling interests
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax	0	0	0	(2)
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, after tax	0	0	0	0
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	0	0	0	0
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, after tax	0		0
Total net unrealized gains (losses) on securities	0	0	0	0
Net unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax	0	0	0	0
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax	0	0	0	0
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, after tax	0		0
Total net unrealized gains (losses) on cash flow hedges	0	0	0	0
Foreign currency translation adjustments	0	0	0	(2)
Pension and other postretirement plans (“OPRP”) adjustments:
Unrealized holding gains (losses) on pension and OPRP arising during the period, after tax	0		0
Reclassification adjustment for pension settlement loss included in net earnings	0		0
Total pension and OPRP adjustments	0	0	0	0
Attributable to shareholders
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax	(777)	1,021	(1,083)	190
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, after tax	(133)	(1,021)	148	(156)
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	(7)	(7)	(18)	12
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, after tax	(884)		(884)
Total net unrealized gains (losses) on securities	(758)	1,014	(1,050)	168
Net unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax	6	12	(1)	48
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax	(4)	(9)	(11)	(18)
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, after tax	(29)		(29)
Total net unrealized gains (losses) on cash flow hedges	(27)	3	(41)	30
Foreign currency translation adjustments	0	4	0	(8)
Pension and other postretirement plans (“OPRP”) adjustments:
Unrealized holding gains (losses) on pension and OPRP arising during the period, after tax	(1)		(1)
Reclassification adjustment for pension settlement loss included in net earnings	9		9
Total pension and OPRP adjustments	8	0	8	0
Accumulated net investment gain (loss) attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	963	16	1,255	862
Reclassify AOCI	205	1,030	205	1,030
AOCI ending balance	205	1,030	205	1,030
Accumulated gain (loss), net, cash flow hedge, parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	27	44	41	17
Reclassify AOCI	0	47	0	47
AOCI ending balance	0	47	0	47
Accumulated foreign currency adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(16)	(21)	(16)	(9)
Reclassify AOCI	(16)	(17)	(16)	(17)
AOCI ending balance	(16)	(17)	(16)	(17)
Accumulated defined benefit plans adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(7)	(7)	(7)	(7)
Reclassify AOCI	1	(7)	1	(7)
AOCI ending balance	1	(7)	1	(7)
AOCI attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	967	32	1,273	863
Reclassify AOCI	190	1,053	190	1,053
AOCI ending balance	$ 190	$ 1,053	$ 190	$ 1,053