Accumulated Other Comprehensive Income (Loss) by Component (Schedule of Accumulated Other Comprehensive Income (Loss) by Component) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	$ 12,809	$ 12,707
Other comprehensive income (loss) before reclassifications	(4,022)	(444)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(145)	39
Other comprehensive income (loss) after tax (expense) benefit	(3,877)	(483)
Total stockholder's equity at end of period	8,825	12,809
Reclassification from AOCI, tax	26	(10)
Tax (expense) benefit on other comprehensive income (loss)	1,005	124
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	320	803
Total stockholder's equity at end of period	(3,557)	320
Net unrealized gains (losses) on investments | 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	(2)	0
Other comprehensive income (loss) before reclassifications	0	(7)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	5	(5)
Other comprehensive income (loss) after tax (expense) benefit	(5)	(2)
Total stockholder's equity at end of period	(7)	(2)
Reclassification from AOCI, tax	(1)	1
Tax (expense) benefit on other comprehensive income (loss)	1	1
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on other investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	1,039	1,745
Other comprehensive income (loss) before reclassifications	(3,903)	(625)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(126)	81
Other comprehensive income (loss) after tax (expense) benefit	(3,777)	(706)
Total stockholder's equity at end of period	(2,738)	1,039
Reclassification from AOCI, tax	21	(21)
Tax (expense) benefit on other comprehensive income (loss)	1,007	188
Pension and postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(604)	(848)
Other comprehensive income (loss) before reclassifications	(11)	207
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(24)	(37)
Other comprehensive income (loss) after tax (expense) benefit	13	244
Total stockholder's equity at end of period	(591)	(604)
Reclassification from AOCI, tax	6	10
Tax (expense) benefit on other comprehensive income (loss)	(3)	(65)
Cumulative foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(113)	(94)
Other comprehensive income (loss) before reclassifications	(108)	(19)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	0	0
Other comprehensive income (loss) after tax (expense) benefit	(108)	(19)
Total stockholder's equity at end of period	(221)	(113)
Reclassification from AOCI, tax	0	0
Tax (expense) benefit on other comprehensive income (loss)	$ 0	$ 0