Shareholders' Equity - Progression of the components of accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	$ (319)
Other comprehensive income (loss), pretax	5	$ 117
Other comprehensive income (loss), tax	(1)	(25)
Other comprehensive income, net of tax	4	92
AOCI ending balance	(315)
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, pretax	6	78
Unrealized holding gains (losses) on securities arising during the period, tax	(1)	(17)
Unrealized holding gains (losses) on securities arising during the period, after tax	5	61
Reclassification adjustment for realized (gains) losses included in net earnings, pretax	5	29
Reclassification adjustment for realized (gains) losses included in net earnings, tax	(1)	(6)
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	4	23
Total net unrealized gains (losses) on securities, pretax	11	107
Total net unrealized gains (losses) on securities, tax	(2)	(23)
Total net unrealized gains (losses) on securities	9	84
Net unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) on cash flow hedges arising during the period, pretax	(13)	5
Unrealized holding gains (losses) on cash flow hedges arising during the period, tax	3	(1)
Unrealized holding gains (losses) on cash flow hedges arising during the period, after tax	(10)	4
Reclassification adjustment for investment income included in net earnings, pretax	7	5
Reclassification adjustment for investment income included in net earnings, tax	(2)	(1)
Reclassification adjustment for investment income included in net earnings from discontinued operations, after tax	5	4
Total net unrealized gains (losses) on cash flow hedges, pretax	(6)	10
Total net unrealized gains (losses) on cash flow hedges, tax	1	(2)
Total net unrealized gains (losses) on cash flow hedges	(5)	8
Foreign currency translation adjustments, pretax	0	0
Foreign currency translation adjustments, tax	0	0
Foreign currency translation adjustments, after tax	0	0
Total pension and OPRP adjustments, pretax	0	0
Total pension and OPRP adjustments, tax	0	0
Total pension and OPRP adjustments, after Tax	0	0
AOCI attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(319)	(543)
AOCI ending balance	(315)	(451)
Accumulated net investment gain (loss) attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(287)	(497)
AOCI ending balance	(278)	(413)
Accumulated gain (loss), net, cash flow hedge, parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(17)	(29)
AOCI ending balance	(22)	(21)
Accumulated foreign currency adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(17)	(20)
AOCI ending balance	(17)	(20)
Accumulated defined benefit plans adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	2	3
AOCI ending balance	$ 2	$ 3