Fair Value Measurements - Carrying and Estimated Fair Value of Debt (Details) - Unsecured Debt $ in Millions	Sep. 30, 2026 USD ($)
3.000% Notes
Debt Instrument [Line Items]
Carrying value	$ 300
7.375% Debentures
Debt Instrument [Line Items]
Carrying value	101
3.450% Notes
Debt Instrument [Line Items]
Carrying value	300
5.125% Notes
Debt Instrument [Line Items]
Carrying value	1,727
4.375% Notes
Debt Instrument [Line Items]
Carrying value	750
Term Loan Credit Facility
Debt Instrument [Line Items]
Carrying value	1,500
2.625% Notes
Debt Instrument [Line Items]
Carrying value	$ 500
5.250% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	5.25%
Carrying value	$ 675
Level 2 \| 3.000% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	3.00%
Estimated fair value	$ 299
Level 2 \| 7.375% Debentures
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	7.375%
Estimated fair value	$ 102
Level 2 \| 3.450% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	3.45%
Estimated fair value	$ 294
Level 2 \| 5.125% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	5.125%
Estimated fair value	$ 1,727
Level 2 \| 4.375% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	4.375%
Estimated fair value	$ 733
Level 2 \| 2.625% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	2.625%
Estimated fair value	$ 451
Level 2 \| 5.250% Notes
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (as a percent)	5.25%
Estimated fair value	$ 606
Level 3 \| Term Loan Credit Facility
Debt Instrument [Line Items]
Estimated fair value	$ 1,500