Fair Value (Carrying and Fair Value By Level of Financial Instruments Not Recorded At Fair Value On Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets, long-term	$ 5,685	$ 5,225
Convertible debentures	63
Gains (losses) recognized in net income	(1)	19	$ (22)
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets, long-term	5,582	5,087
Short-term borrowings	265	275
Commercial paper		300
Notes	23,786	22,384
Convertible debentures	63	72
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets, long-term	5,582	5,087
Short-term borrowings	265	275
Commercial paper		300
Notes	21,861	25,150
Convertible debentures	463	687
Fair Value, Recurring [Member] | Level I [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term borrowings		0
Fair Value, Recurring [Member] | Level II [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets, long-term	0	0
Short-term borrowings	265	275
Commercial paper		300
Notes	21,861	25,150
Convertible debentures	463	687
Fair Value, Recurring [Member] | Level III [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets, long-term	5,582	5,087
Short-term borrowings	0	0
Commercial paper		0
Notes	0	0
Convertible debentures	$ 0	$ 0