Financial Instruments (Cost and Fair Value of Available-For-Sale Debt Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Available-for-sale debt securities
Cost	$ 210	$ 203
Fair Value	209	204
Cost
Within one year	66	63
One to five years	133	128
Six to ten years	2	2
After ten years	9	10
Cost	210	203
Fair Value
Within one year	66	63
One to five years	132	129
Six to ten years	2	2
After ten years	9	10
Fair Value	209	204
Corporate bonds
Available-for-sale debt securities
Cost	115	108
Fair Value	115	109
Cost
Cost	115	108
Fair Value
Fair Value	115	109
U.S. government treasury securities
Available-for-sale debt securities
Cost	40	37
Fair Value	39	37
Cost
Cost	40	37
Fair Value
Fair Value	39	37
U.S. federal agency securities
Available-for-sale debt securities
Cost	11	13
Fair Value	11	13
Cost
Cost	11	13
Fair Value
Fair Value	11	13
Asset-backed securities
Available-for-sale debt securities
Cost	39	37
Fair Value	39	37
Cost
Cost	39	37
Fair Value
Fair Value	39	37
Supranational securities
Available-for-sale debt securities
Cost	5	8
Fair Value	5	8
Cost
Cost	5	8
Fair Value
Fair Value	$ 5	$ 8

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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