Shareholders' Equity - Progression of the components of accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	$ 119
Other comprehensive income (loss), pretax	(318)	$ (386)
Other comprehensive income (loss), tax	68	80
Other comprehensive loss, net of tax	(250)	(306)
AOCI ending balance	(131)
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period, pretax	(313)	(355)
Unrealized holding gains (losses) on securities arising during the period, tax	66	74
Unrealized holding gains (losses) on securities arising during the period, after tax	247	281
Reclassification adjustment for realized (gains) losses included in net earnings, pretax	2	(14)
Reclassification adjustment for realized (gains) losses included in net earnings, tax	0	3
Reclassification adjustment for realized (gains) losses included in net earnings, after tax	2	(11)
Total net unrealized gains (losses) on securities, pretax	(311)	(369)
Total net unrealized gains (losses) on securities, tax	66	77
Total net unrealized losses on securities	(245)	(292)
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Net unrealized gains (losses) on cash flow hedges, pretax	(5)	(17)
Net unrealized gains (losses) on cash flow hedges, tax	1	3
Total net unrealized gains (losses) on cash flow hedges	(4)	(14)
Foreign currency translation adjustments, pretax	(2)	0
Foreign currency translation adjustments, tax	1	0
Foreign currency translation adjustments	(1)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent [Abstract]
Pension and OPRP adjustments, pretax	0	0
Pension and OPRP adjustments, tax	0	0
Pension and OPRP adjustments, after tax	0	0
Accumulated net investment gain (loss) attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	136	1,255
AOCI ending balance	(109)	963
Accumulated gain (loss), net, cash flow hedge, parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	0	41
AOCI ending balance	(4)	27
Accumulated foreign currency adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	(18)	(16)
AOCI ending balance	(19)	(16)
Accumulated defined benefit plans adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	1	(7)
AOCI ending balance	1	(7)
AOCI attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance	119	1,273
AOCI ending balance	$ (131)	$ 967