Hedging Activities - Schedule of Notional Amounts of Outstanding Derivatives (Details) - Derivatives designated for hedge accounting € in Millions, £ in Millions, $ in Millions, $ in Millions	Dec. 31, 2024 CAD ($)	Dec. 31, 2024 GBP (£)	Dec. 31, 2024 EUR (€)	Dec. 31, 2024 USD ($)	Jun. 30, 2024 CAD ($)	Mar. 31, 2024 CAD ($)	Mar. 31, 2024 GBP (£)	Mar. 31, 2024 EUR (€)	Mar. 31, 2024 USD ($)	Jun. 15, 2023 USD ($)	Mar. 31, 2023 USD ($)
Cross-currency swaps | Net Investment Hedges | CAD
Derivatives, Fair Value [Line Items]
Notional	$ 3,500				$ 2,500	$ 1,500
Cross-currency swaps | Fair Value Hedges | GBP
Derivatives, Fair Value [Line Items]
Notional | £		£ 450					£ 450
Cross-currency swaps | Fair Value Hedges | EUR
Derivatives, Fair Value [Line Items]
Notional | €			€ 1,100					€ 1,100
Floating interest rate swaps | Fair Value Hedges
Derivatives, Fair Value [Line Items]
Notional				$ 1,300							$ 1,300
Floating interest rate swaps | Fair Value Hedges | USD
Derivatives, Fair Value [Line Items]
Notional				$ 750					$ 1,250
Floating interest rate swaps | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Notional										$ 500
Foreign currency forwards | Cash Flow Hedges | GBP
Derivatives, Fair Value [Line Items]
Notional | £		£ 19					£ 39