Shareholders' Equity - Progression of the components of accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			$ 1,273
Other comprehensive income (loss), pretax	$ (38)	$ 223	(1,409)	$ 468
Other comprehensive income (loss), tax	8	(47)	296	(100)
Other comprehensive income (loss), net of tax	(30)	176	(1,113)	368
Accumulated other comprehensive income, net of tax	160		160
AOCI ending balance	160		160
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, pretax	(37)	245	(224)	443
Unrealized holding gains (losses) on securities arising during the period, tax	8	(51)	47	(93)
Unrealized holding gains (losses) on securities arising during the period, after tax	29	(194)	177	(350)
Reclassification adjustment for realized (gains) losses included in net earnings, pretax	2	(15)	(21)	0
Reclassification adjustment for realized (gains) losses included in net earnings, tax	0	3	5	0
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	2	(12)	(16)	0
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, pretax			(1,119)
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, tax			235
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, after tax	0	0	(884)	0
Total net unrealized gains (losses) on securities, pretax	(35)	230	(1,364)	443
Total net unrealized gains (losses) on securities, tax	8	(48)	287	(93)
Total net unrealized gains (losses) on securities	(27)	182	(1,077)	350
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Unrealized holding gains (losses) on cash flow hedges arising during the period, pretax		1	(1)	62
Unrealized holding gains (losses) on cash flow hedges arising during the period, tax		0	0	(13)
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax	0	1	(1)	49
Reclassification adjustment for investment income included in net earnings from discontinued operations, pretax		(8)	(14)	(31)
Reclassification adjustment for investment income included in net earnings from discontinued operations, tax		1	3	6
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax	0	(7)	(11)	(25)
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, pretax			(37)
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, tax			8
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, after tax	0	0	(29)	0
Total net unrealized gains (losses) on cash flow hedges, pretax		(7)	(52)	31
Total net unrealized gains (losses) on cash flow hedges, tax		1	11	(7)
Total net unrealized gains (losses) on cash flow hedges	0	(6)	(41)	24
Foreign currency translation adjustments, pretax	(3)	0	(3)	(6)
Foreign currency translation adjustments, tax	0	0	0	0
Foreign currency translation adjustments	(3)	0	(3)	(6)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent [Abstract]
Unrealized holding gains (losses) on pension and OPRP arising during the period, pretax			(1)
Unrealized holding gains (losses) on pension and OPRP arising during the period, tax			0
Unrealized holding gains (losses) on pension and OPRP arising during the period, after tax	0	0	(1)	0
Reclassification adjustment for pension settlement loss included in other expense in net earnings, pretax			11
Reclassification adjustment for pension settlement loss included in other expense in net earnings, tax			(2)
Reclassification adjustment for pension settlement loss included in net earnings	0	0	9	0
Total pension and OPRP adjustments, pretax	0	0	10	0
Total pension and OPRP adjustments, tax	0	0	(2)	0
Total pension and OPRP adjustments	0	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
Total net unrealized gains (losses) on securities	0	0	0	0
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax		0	0	0
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax		0	0	0
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, after tax			0
Total net unrealized gains (losses) on cash flow hedges		0	0	0
Foreign currency translation adjustments	0	0	0	(2)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent [Abstract]
Unrealized holding gains (losses) on pension and OPRP arising during the period, after tax			0
Reclassification adjustment for pension settlement loss included in net earnings			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	(30)	176	(1,113)	366
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, after tax	29	(194)	177	(350)
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	2	(12)	(16)	0
Reclassification adjustment for unrealized gains (losses) on securities of subsidiaries sold, after tax			(884)
Total net unrealized gains (losses) on securities	(27)	182	(1,077)	350
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax		1	(1)	49
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax		(7)	(11)	(25)
Reclassification for unrealized gains on cash flow hedges of subsidiaries sold, after tax			(29)
Total net unrealized gains (losses) on cash flow hedges		(6)	(41)	24
Foreign currency translation adjustments	(3)	0	(3)	(8)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent [Abstract]
Unrealized holding gains (losses) on pension and OPRP arising during the period, after tax			(1)
Reclassification adjustment for pension settlement loss included in net earnings			9
Total pension and OPRP adjustments	0	0	8	0
Accumulated net investment gain (loss) attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	205	1,030	1,255	862
Accumulated other comprehensive income, net of tax	178	1,212	178	1,212
AOCI ending balance	178	1,212	178	1,212
Accumulated gain (loss), net, cash flow hedge, parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance		47	41	17
Accumulated other comprehensive income, net of tax	0	41	0	41
AOCI ending balance	0	41	0	41
Accumulated foreign currency adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(16)	(17)	(16)	(9)
Accumulated other comprehensive income, net of tax	(19)	(13)	(19)	(13)
AOCI ending balance	(19)	(13)	(19)	(13)
Accumulated foreign currency adjustment attributable to parent | Neon Capital Limited
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, net of tax		4		4
AOCI ending balance		4		4
Accumulated defined benefit plans adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	1	(7)	(7)	(7)
Accumulated other comprehensive income, net of tax	1	(7)	1	(7)
AOCI ending balance	1	(7)	1	(7)
AOCI attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	190	1,053	1,273	863
Accumulated other comprehensive income, net of tax	160	1,233	160	1,233
AOCI ending balance	$ 160	1,233	$ 160	1,233
AOCI attributable to parent | Neon Capital Limited
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, net of tax		4		4
AOCI ending balance		$ 4		$ 4