Short-Term and Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 250	$ 500
Debt, Current, Total	250	500
Term loan and subordinated notes	995	995
Total long-term debt	$ 5,699	5,955
Debt repurchase option	100.00%
Fixed interest rate	5.00%
Senior notes
Debt Instrument [Line Items]
Senior notes	$ 4,368	4,368
Term loan
Debt Instrument [Line Items]
Term loan and subordinated notes	0	250
Capital securities
Debt Instrument [Line Items]
Capital securities	218	218
Long-term debt
Debt Instrument [Line Items]
Unamortized premiums (discounts)	(6)	(6)
Unamortized debt issuance costs	(30)	(34)
Unamortized adjustments from discontinued hedges	326	341
Fair value hedge on interest rate swap agreements	(172)	(177)
Total long-term debt	5,699	5,955
3.35% notes, due 2025 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 300	300
Debt instrument, interest rate, stated percentage	3.35%
3.625% notes, due 2026 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 400	400
Debt instrument, interest rate, stated percentage	3.625%
3.80% notes, due 2028 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 500	500
Debt instrument, interest rate, stated percentage	3.80%
3.05% notes, due 2030 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 500	500
Debt instrument, interest rate, stated percentage	3.05%
3.40% notes, due 2031 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 500	500
Debt instrument, interest rate, stated percentage	3.40%
3.40% notes, due 2032 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 300	300
Debt instrument, interest rate, stated percentage	3.40%
6.15% notes, due 2036 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 243	243
Debt instrument, interest rate, stated percentage	6.15%
6.30% notes, due 2037 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 375	375
Debt instrument, interest rate, stated percentage	6.30%
7.00% notes, due 2040 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 500	500
Debt instrument, interest rate, stated percentage	7.00%
4.35% notes, due 2048 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 450	450
Debt instrument, interest rate, stated percentage	4.35%
4.375% notes, due 2050 | Senior notes
Debt Instrument [Line Items]
Senior notes	$ 300	300
Debt instrument, interest rate, stated percentage	4.375%
Term loan due 2024 | Term loan
Debt Instrument [Line Items]
Term loan and subordinated notes	$ 0	250
Term loan due 2024 | Term loan | Variable Rate Component One | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.10%
Term loan due 2024 | Term loan | Variable Rate Component Two | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.125%
SOFR + 236 bps, due 2066 | Subordinated notes
Debt Instrument [Line Items]
Term loan and subordinated notes	$ 562	562
SOFR + 236 bps, due 2066 | Subordinated notes | Variable Rate Component One | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.36%
SOFR + 236 bps, due 2066 | Capital securities
Debt Instrument [Line Items]
Capital securities	$ 160	160
SOFR + 236 bps, due 2066 | Capital securities | Variable Rate Component One | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.26161%
SOFR + 236 bps, due 2066 | Capital securities | Variable Rate Component Two | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.36%
SOFR + 204 bps, due 2067 | Subordinated notes
Debt Instrument [Line Items]
Term loan and subordinated notes	$ 433	433
SOFR + 204 bps, due 2067 | Subordinated notes | Variable Rate Component Two | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.04%
SOFR + 204 bps, due 2067 | Capital securities
Debt Instrument [Line Items]
Capital securities	$ 58	$ 58
SOFR + 204 bps, due 2067 | Capital securities | Variable Rate Component One | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.26161%
SOFR + 204 bps, due 2067 | Capital securities | Variable Rate Component Two | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.04%