Investments Investments (Schedule of Gains and Losses on Equity and Other Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Unrealized Gain (Loss) on Investments	$ (2,417)	$ 2,130	$ 3,088
Net realized gains (losses) (includes $3, $(281), and $(31) reclassified from AOCI)	1,152	(498)	(530)
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	662	586	104	[1]
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) (includes $3, $(281), and $(31) reclassified from AOCI)	111	(32)	(20)
Accounting Standards Update 2016-01 [Member] | Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	662	586	104
Unrealized Gain (Loss) on Investments	505	131	46
Gain (Loss) on Sale of Investments	157	455	58
Accounting Standards Update 2016-01 [Member] | Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Unrealized Gain (Loss) on Investments	111	(32)	(15)
Gain (Loss) on Sale of Investments	0	0	(5)
Net realized gains (losses) (includes $3, $(281), and $(31) reclassified from AOCI)	111	(32)	(20)
Accounting Standards Update 2016-01 [Member] | Equity securities and other investments [Member]
Gain (Loss) on Securities [Line Items]
Unrealized Gain (Loss) on Investments	616	99	31
Gain (Loss) on Sale of Investments	157	455	53
Net realized gains (losses) (includes $3, $(281), and $(31) reclassified from AOCI)	$ 773	$ 554	$ 84

[1] Relates to certain securities we intended to sell and securities written to market entering default.