10-K Debt - Carrying Value Of Long-Term Debt (Details) - USD ($) $ in Millions	Sep. 30, 2023	Mar. 15, 2023	Jan. 17, 2023	Dec. 31, 2022	Dec. 01, 2022	Nov. 04, 2022	May 16, 2022	Apr. 29, 2022	Dec. 31, 2021	Mar. 17, 2021	May 05, 2020	Oct. 09, 2012
Debt Instrument [Line Items]
Long-term Debt				$ 23,849					$ 22,756
Long-Term Debt, Current Maturities	$ (799)			(1,500)					(1,599)
Long-term debt, less current portion	24,045			22,349					21,157
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	24,819			23,761
Surplus Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 25			25
Commercial Paper
Debt Instrument [Line Items]
Commercial paper				$ 0					300
Two Point Nine Five Zero Percent Due Two Thousand Twenty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				2.95%	2.95%
Long-term Debt				$ 0					749
Three Point One Two Five Percent Due Two Thousand Twenty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.125%			3.125%
Long-term Debt				$ 0					850
Three Point Three Zero Zero Percent Due Two Thousand Twenty Three | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate			3.30%	3.30%
Long-term Debt				$ 1,000					1,014
Zero Point Four Five Zero Percent Due Two Thousand Twenty Three | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate		0.45%		0.45%						0.45%
Long-term Debt				$ 500					499
Three Point Three Five Zero Percent Due Two Thousand Twenty Four | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.35%
Long-term Debt				$ 849					848
Three Point Five Zero Zero Percent Due Two Thousand Twenty Four | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.50%
Long-term Debt				$ 798					797
Two Point Three Seven Five Percent Due Two Thousand Twenty Five | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				2.375%
Long-term Debt				$ 1,252					1,253
Five Point Three Five Zero Percent Due Two Thousand Twenty Five | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.35%		5.35%
Long-term Debt				$ 398					0
One Point Five Zero Zero Percent Due Two Thousand Twenty Six | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				1.50%						1.50%
Long-term Debt				$ 746					745
Three Point Six Five Zero Percent Due Two Thousand Twenty Seven | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.65%
Long-term Debt				$ 1,592					1,592
Four Point One Zero One Percent Due Two Thousand Twenty Eight | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.101%
Long-term Debt				$ 1,234					1,251
Two Point Eight Seven Five Percent Due Two Thousand Twenty Nine | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				2.875%
Long-term Debt				$ 820					820
Two Point Two Five Zero Percent Due Two Thousand Thirty | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				2.25%							2.25%
Long-term Debt				$ 1,071					1,089
Two Point Five Five Zero Percent Due Two Thousand Thirty One | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				2.55%						2.55%
Long-term Debt				$ 968					992
Four Point One Zero Percent Due Two Thousand Thirty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.10%				4.10%
Long-term Debt				$ 595					0
Five Point Five Zero Zero Percent Due Two Thousand Thirty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.50%		5.50%
Long-term Debt				$ 644					0
Five Point Nine Five Zero Percent Due Two Thousand Thirty Four | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.95%
Long-term Debt				$ 334					334
Five Point Eight Five Zero Percent Due Two Thousand Thirty Six | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.85%
Long-term Debt				$ 396					396
Six Point Three Seven Five Percent Due Two Thousand Thirty Seven | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				6.375%
Long-term Debt				$ 364					364
Five Point Eight Zero Zero Percent Due Two Thousand Forty | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.80%
Long-term Debt				$ 114					114
Four Point Six Two Five Percent Due Two Thousand Forty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.625%
Long-term Debt				$ 859					859
Four Point Six Five Zero Percent Due Two Thousand Forty Three | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.65%
Long-term Debt				$ 974					974
Four Point Six Five Zero Percent Due Two Thousand Forty Four | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.65%
Long-term Debt				$ 767					767
Five Point One Zero Zero Percent Due Two Thousand Forty Four | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.10%
Long-term Debt				$ 548					548
Four Point Three Seven Five Percent Due Two Thousand Forty Seven | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.375%
Long-term Debt				$ 1,388					1,387
Four Point Five Five Zero Percent Due Two Thousand Forty Eight | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.55%
Long-term Debt				$ 840					839
Three Point Seven Zero Zero Percent Due Two Thousand Forty Nine | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.70%
Long-term Debt				$ 812					812
Three Point One Two Five Percent Due Two Thousand Fifty | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.125%							3.125%
Long-term Debt				$ 988					987
Three Point Six Zero Zero Percent Due Two Thousand Fifty One | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				3.60%						3.60%
Long-term Debt				$ 1,233					1,232
Four Point Five Five Zero Due Two Thousand Fifty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.55%				4.55%
Long-term Debt				$ 689					0
Six Point One Zero Zero Percent Due Two Thousand Fifty Two | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				6.10%		6.10%
Long-term Debt				$ 741					0
Four Point Eight Five Zero Percent Due Two Thousand Fifty Four | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				4.85%
Long-term Debt				$ 247					247
Nine Point Zero Zero Zero Percent Due Two Thousand Twenty Seven | Surplus Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				9.00%
Long-term Debt				$ 25					25
Two Point Seven Five Zero Percent Due Two Thousand Forty Two | Senior Convertible Debenture [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				2.75%								2.75%
Long-term Debt				$ 63					$ 72