Fair Value of Financial Instruments (Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($)	Sep. 30, 2025	Dec. 31, 2024
Debt Securities [Abstract]
Financial investments	$ 53,000,000	$ 184,000,000
Total assets at fair value	0	0
Fair value, recurring
Debt Securities [Abstract]
Financial investments	53,000,000	184,000,000
Equity securities	49,000,000	2,000,000
Total assets at fair value	102,000,000	186,000,000
Fair value, recurring \| Level 1
Debt Securities [Abstract]
Financial investments	53,000,000	166,000,000
Equity securities	49,000,000	2,000,000
Total assets at fair value	102,000,000	168,000,000
Fair value, recurring \| Level 2
Debt Securities [Abstract]
Financial investments	0	18,000,000
Equity securities	0	0
Total assets at fair value	0	18,000,000
Fair value, recurring \| Level 3
Debt Securities [Abstract]
Financial investments	0	0
Equity securities	0	0
Total assets at fair value	0	0
Fair value, recurring \| European government debt securities
Debt Securities [Abstract]
Financial investments	52,000,000	166,000,000
Fair value, recurring \| European government debt securities \| Level 1
Debt Securities [Abstract]
Financial investments	52,000,000	166,000,000
Fair value, recurring \| European government debt securities \| Level 2
Debt Securities [Abstract]
Financial investments	0	0
Fair value, recurring \| European government debt securities \| Level 3
Debt Securities [Abstract]
Financial investments	0	0
Fair value, recurring \| Time deposits
Debt Securities [Abstract]
Financial investments	1,000,000	5,000,000
Fair value, recurring \| Time deposits \| Level 1
Debt Securities [Abstract]
Financial investments	1,000,000	0
Fair value, recurring \| Time deposits \| Level 2
Debt Securities [Abstract]
Financial investments	0	5,000,000
Fair value, recurring \| Time deposits \| Level 3
Debt Securities [Abstract]
Financial investments	$ 0	0
Fair value, recurring \| Swedish mortgage bonds
Debt Securities [Abstract]
Financial investments		13,000,000
Fair value, recurring \| Swedish mortgage bonds \| Level 1
Debt Securities [Abstract]
Financial investments		0
Fair value, recurring \| Swedish mortgage bonds \| Level 2
Debt Securities [Abstract]
Financial investments		13,000,000
Fair value, recurring \| Swedish mortgage bonds \| Level 3
Debt Securities [Abstract]
Financial investments		$ 0