Accumulated Other Comprehensive Income (Loss) by Component (Schedule of accumulated other comprehensive income (loss) by component) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period			$ 12,809
Other comprehensive income (loss) before reclassifications	$ (1,532)	$ (155)	(4,591)	$ (413)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(106)	8	(132)	44
Other comprehensive income (loss) after tax (expense) benefit	(1,426)	(163)	(4,459)	(457)
Total stockholder's equity at end of period	8,094	12,664	8,094	12,664
Reclassification from AOCI, tax	13	(3)	19	(12)
Tax (expense) benefit on other comprehensive income (loss)	369	35	1,147	117
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(2,713)	509	320	803
Total stockholder's equity at end of period	(4,139)	346	(4,139)	346
Net unrealized gains (losses) on investments with an allowance for credit losses | Net unrealized gains (losses) on investments with an allowance for credit losses
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(8)	0	(2)	0
Other comprehensive income (loss) before reclassifications	0	0	(5)	(2)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	2	0	3	(2)
Other comprehensive income (loss) after tax (expense) benefit	(2)	0	(8)	0
Total stockholder's equity at end of period	(10)	0	(10)	0
Reclassification from AOCI, tax	0	0	(1)	1
Tax (expense) benefit on other comprehensive income (loss)	1	0	2	0
Net unrealized gains (losses) on investments with an allowance for credit losses | Net unrealized gains (losses) on other investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(1,918)	1,418	1,039	1,745
Other comprehensive income (loss) before reclassifications	(1,429)	(121)	(4,401)	(391)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(102)	17	(117)	74
Other comprehensive income (loss) after tax (expense) benefit	(1,327)	(138)	(4,284)	(465)
Total stockholder's equity at end of period	(3,245)	1,280	(3,245)	1,280
Reclassification from AOCI, tax	11	(5)	15	(20)
Tax (expense) benefit on other comprehensive income (loss)	370	37	1,150	124
Pension and postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(592)	(829)	(604)	(848)
Other comprehensive income (loss) before reclassifications	0	(1)	0	(1)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(6)	(9)	(18)	(28)
Other comprehensive income (loss) after tax (expense) benefit	6	8	18	27
Total stockholder's equity at end of period	(586)	(821)	(586)	(821)
Reclassification from AOCI, tax	2	2	5	7
Tax (expense) benefit on other comprehensive income (loss)	(2)	(2)	(5)	(7)
Cumulative foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(195)	(80)	(113)	(94)
Other comprehensive income (loss) before reclassifications	(103)	(33)	(185)	(19)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	0	0	0	0
Other comprehensive income (loss) after tax (expense) benefit	(103)	(33)	(185)	(19)
Total stockholder's equity at end of period	(298)	(113)	(298)	(113)
Reclassification from AOCI, tax	0	0	0	0
Tax (expense) benefit on other comprehensive income (loss)	$ 0	$ 0	$ 0	$ 0