Shareholders' Equity Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net unrealized securities gains, before tax [Abstract]
Net unrealized securities gains (losses) arising during the period before tax	[1]	$ 907	$ 1,404	$ (1,039)
Reclassification of net securities (gains) losses included in net income before tax	[2]	(11)	6	(9)
Impact of deferred acquisition costs, deferred sales inducement costs, unearned revenue, benefit reserves and reinsurance recoverables before tax		(379)	(688)	435
Net unrealized securities gains before tax		517	722	(613)
Net unrealized derivatives losses, before tax [Abstract]
Reclassification of net derivative losses included in net income before tax	[3]	(2)	(3)
Net unrealized derivatives losses before tax		(2)	(3)
Defined benefit plans, before tax [Abstract]
Prior service credit before tax		(2)	14
Net loss arising during the period before tax		(82)	(36)	(30)
Defined benefit plans before tax		(84)	(22)	(30)
Foreign currency translation before tax		32	18	(32)
Other Comprehensive Income (Loss), before Tax		463	715	(675)
Net unrealized securities gains, tax impact [Abstract]
Net unrealized securities (gains) losses arising during the period tax impact	[1]	(192)	(309)	237
Reclassification of net securities gains (losses) included in net income tax impact	[2]	2	(1)	2
Impact of deferred acquisition costs, deferred sales inducement costs, unearned revenue, benefit reserves and reinsurance recoverables tax impact		80	144	(91)
Net unrealized securities gains tax impact		(110)	(166)	148
Net unrealized derivatives losses, tax impact [Abstract]
Reclassification of net derivative losses included in net income tax impact	[3]	1	1
Net unrealized derivatives losses tax impact		1	1
Defined benefit plans, net of tax [Abstract]
Prior service credit tax impact		0	(3)
Net loss arising during the period tax		18	7	7
Defined benefit plans tax impact		18	4	7
Foreign currency translation tax impact		(5)	(1)	1
Other Comprehensive Income (Loss), Tax		(96)	(162)	156
Net unrealized securities gains, net of tax [Abstract]
Net unrealized securities gains (losses) arising during the period, net of tax	[1]	715	1,095	(802)
Reclassification of net securities (gains) losses included in net income net of tax	[2]	(9)	5	(7)
Impact of deferred acquisition costs, deferred sales inducement costs, unearned revenue, benefit reserves and reinsurance recoverables net of tax		(299)	(544)	344
Net unrealized securities gains net of tax		407	556	(465)
Net unrealized derivative losses, net of tax [Abstract]
Reclassification of net derivative losses included in net income net of tax	[3]	(1)	(2)
Net unrealized derivatives losses net of tax		(1)	(2)
Defined benefit plans, net of tax [Abstract]
Prior service credit net of tax		(2)	11
Net loss arising during the period net of tax		(64)	(29)	(23)
Defined benefit plans net of tax		(66)	(18)	(23)
Foreign currency translation net of tax		27	17	(31)
Total other comprehensive income (loss), net of tax		367	553	(519)
Interest expense [Member]
Amount of gain (loss) reclassified from accumulated other comprehensive income into income		1	2	2
Net investment income [Member]
Amount of gain (loss) reclassified from accumulated other comprehensive income into income		$ 0	$ 0	$ (2)

[1] Includes impairments on Available-for-Sale securities related to factors other than credit that were recognized in OCI during the period.

[2] Reclassification amounts are recorded in net investment income.

[3] Includes a $1 million, $2 million and $2 million pretax gain reclassified to interest and debt expenses and nil, nil and $2 million pretax loss reclassified to net investment income for the years ended December 31, 2020, 2019 and 2018, respectively.