Derivative Instruments (Equity-related Derivative Instruments) (Details) - Vodafone Collar Loan € in Millions, $ in Millions	Feb. 11, 2023 EUR (€) shares	Sep. 30, 2023 EUR (€)	Sep. 30, 2023 USD ($)	Feb. 11, 2023 USD ($)
Derivative [Line Items]
Stock issued during period, shares, new issues	1,335,000,000
Debt instrument, face amount	€ 1,143.6	€ 1,258.0	$ 1,341.8	$ 1,219.8
Debt instrument, unamortized discount		€ 114.4	$ 122.0
Stated interest percentage		2.95%	2.95%