10-Q Debt (Narrative) (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 15, 2023	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Feb. 08, 2023	Jan. 17, 2023	Jul. 31, 2022	Jan. 01, 2022	Mar. 17, 2021	Oct. 09, 2012
Debt Instrument [Line Items]
Long-term Debt						$ 23,849,000,000	$ 22,756,000,000
Debt Instrument, Face Amount						63,000,000
Repayments of Long-term Debt				$ 1,908,000,000	$ 982,000,000	1,899,000,000	1,068,000,000	$ 1,932,000,000
Short-term borrowings		$ 0		$ 0		265,000,000	275,000,000
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2020-06 [Member] | Retained Earnings [Member]
Debt Instrument [Line Items]
Long-term Debt							31,000,000					$ 31,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Covenant description				Our ability to borrow under the 5-Year Facility is subject to compliance with certain covenants, including covenants requiring us to maintain a defined debt-to-capital ratio of not more than 60%, subject to increase in certain circumstances set forth in the credit agreement for the 5-Year Facility.
Covenant compliance				As of September 30, 2023, our debt-to-capital ratio, as defined and calculated under the 5-Year Facility, was 39.2%. We do not believe the restrictions contained in our 5-Year Facility covenants materially affect our financial or operating flexibility. As of September 30, 2023, we were in compliance with all of our debt covenants under the 5-Year Facility.
Maximum borrowing capacity		4,000,000,000		$ 4,000,000,000
Subsidiary Credit Facilities [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 200,000,000
Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Debt instrument interest rate						4.24%
Federal Home Loan Bank, advances, short-term		0		0		$ 265,000,000
Surplus Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		25,000,000		25,000,000		25,000,000
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		24,819,000,000		24,819,000,000		23,761,000,000
Senior Unsecured Notes [Member] | Four Point Nine Zero Zero Percent Due Two Thousand Twenty Six
Debt Instrument [Line Items]
Debt instrument interest rate									4.90%
Debt Instrument, Face Amount									$ 500,000,000
Senior Unsecured Notes [Member] | Four Point Seven Five Zero Percent Due Two Thousand Thirty Three
Debt Instrument [Line Items]
Debt instrument interest rate									4.75%
Debt Instrument, Face Amount									$ 1,000,000,000
Senior Unsecured Notes [Member] | Five Point One Two Five Percent Due Two Thousand Fifty Three
Debt Instrument [Line Items]
Debt instrument interest rate									5.125%
Debt Instrument, Face Amount									$ 1,100,000,000
Senior Unsecured Notes [Member] | Three Point Three Zero Zero Percent Due Two Thousand Twenty Three
Debt Instrument [Line Items]
Long-term Debt						$ 1,000,000,000	1,014,000,000
Debt instruments, repurchased face amount										$ 1,000,000,000
Debt instrument interest rate						3.30%				3.30%
Senior Unsecured Notes [Member] | Zero Point Four Five Zero Percent Due Two Thousand Twenty Three
Debt Instrument [Line Items]
Long-term Debt						$ 500,000,000	499,000,000
Debt instruments, repurchased face amount	$ 500,000,000
Debt instrument interest rate	0.45%					0.45%							0.45%
Debt Instrument, Face Amount													$ 500,000,000
Commercial Paper
Debt Instrument [Line Items]
Commercial paper authorized		4,000,000,000		$ 4,000,000,000		$ 4,000,000,000	3,500,000,000				$ 4,000,000,000
Commercial paper						0	300,000,000
Senior Convertible Debenture [Member] | Two Point Seven Five Zero Percent Due Two Thousand Forty Two
Debt Instrument [Line Items]
Long-term Debt						$ 63,000,000	72,000,000
Debt instrument interest rate						2.75%								2.75%
Debt Instrument, Face Amount						$ 1,000								$ 1,500,000,000
Debt Conversion Debt Principal Amount			$ 59,000,000			41,000,000	54,000,000	56,000,000
Repayments of Long-term Debt	$ 5,000,000	$ 404,000,000				$ 299,000,000	$ 302,000,000	$ 222,000,000
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	100.00%