Significant Accounting Policies (Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 11,704	$ 11,055	$ 10,401
Other comprehensive income (loss) before reclassifications	(14)	37
Amounts reclassified from Accumulated other comprehensive loss	1	4
Other comprehensive income (loss)	(13)	41	(5)
Ending balance	12,308	11,704	11,055
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(26)	(67)	(62)
Other comprehensive income (loss)	(13)	41	(5)
Ending balance	(39)	(26)	(67)
Net Unrealized Gain (Loss) on Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	30	(17)
Other comprehensive income (loss) before reclassifications	(8)	47
Amounts reclassified from Accumulated other comprehensive loss	(3)	0
Other comprehensive income (loss)	(11)	47
Ending balance	19	30	(17)
Benefit Obligations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(51)	(52)
Other comprehensive income (loss) before reclassifications	(9)	(3)
Amounts reclassified from Accumulated other comprehensive loss	4	4
Other comprehensive income (loss)	(5)	1
Ending balance	(56)	(51)	(52)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(5)	2
Other comprehensive income (loss) before reclassifications	3	(7)
Amounts reclassified from Accumulated other comprehensive loss	0	0
Other comprehensive income (loss)	3	(7)
Ending balance	$ (2)	$ (5)	$ 2