Debt and Credit Agreements - Narrative (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2026 USD ($) swap	Mar. 31, 2025 swap	Dec. 31, 2023 swap	Dec. 31, 2022 swap	Dec. 31, 2025 USD ($)
Commercial Paper
Line of Credit Facility
Line of credit facility capacity	$ 1,000,000,000.0
Line of credit facility, amount outstanding	0
Two Separate Fixed-to-Floating Interest Rate Swaps Due 2055 | Fair Value Hedging
Line of Credit Facility
Derivative, number of fair value hedges | swap		2
Derivative, term of contract		10 years
Two Separate Fixed-to-Floating Interest Rate Swaps Due 2055 | Fair Value Hedging | Designated as Hedging Instrument
Line of Credit Facility
Interest rate fair value hedge asset at fair value	$ 7,000,000				$ 9,000,000
Seven Fixed-to-Floating Interest Rate Swaps | Fair Value Hedging
Line of Credit Facility
Derivative, number of fair value hedges | swap	7
Derivative, term of contract	10 years
Two Separate Fixed-to-Floating Interest Rate Swaps | Fair Value Hedging
Line of Credit Facility
Derivative, number of fair value hedges | swap			2
Five Separate Fixed-to-Floating Interest Rate Swaps | Fair Value Hedging
Line of Credit Facility
Derivative, number of fair value hedges | swap				5
Five Separate Fixed-to-Floating Interest Rate Swaps | Fair Value Hedging | Designated as Hedging Instrument
Line of Credit Facility
Interest rate fair value hedge liability at fair value	$ 92,000,000				87,000,000
2023 Fixed-to-Floating Interest Rate Swaps | Fair Value Hedging | Designated as Hedging Instrument
Line of Credit Facility
Interest rate fair value hedge asset at fair value	12,000,000				14,000,000
Interest Rate Swap | Cash Flow Hedging | Designated as Hedging Instrument
Line of Credit Facility
Derivative asset, notional value	500,000,000
Derivative asset, unsettled notional amount	0				$ 0
Two Separate Fixed-to-Floating Interest Rate Swaps Due 2055
Line of Credit Facility
Notional value of hedged notes	250,000,000
Seven Fixed-to-Floating Interest Rate Swaps
Line of Credit Facility
Notional value of hedged notes	1,100,000,000
3.25% Notes Due 2027
Line of Credit Facility
Notional value of hedged notes	$ 850,000,000
Interest rate	3.25%
Unsecured Revolving Credit Facility Due 2028 | Revolving Credit Facility
Line of Credit Facility
Line of credit facility capacity	$ 1,200,000,000
Line of credit facility, amount outstanding	$ 0