Non-Derivatives Used in Net Investment Hedge, Increase (Decrease), Gross of Tax

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Nominal or face amount used to calculate payment on derivative.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

Amount, after tax and reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount, before tax and reclassification, of gain (loss) from derivative designated and qualifying as net investment hedge.

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- Definition

The cash inflow provided by derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments.

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Amount, before tax, of increase (decrease) in the cumulative translation adjustment from gain (loss) on foreign currency derivatives that are designated as, and are effective as, economic hedges of a net investment in a foreign entity.

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Hedging Activities - Narrative (Details) £ in Millions	3 Months Ended		9 Months Ended
Hedging Activities - Narrative (Details) £ in Millions	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2020 CAD ($)	Dec. 31, 2020 GBP (£)	Nov. 30, 2020 CAD ($)	Apr. 27, 2020 USD ($)	Apr. 27, 2020 EUR (€)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 EUR (€)	Mar. 31, 2020 CAD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 GBP (£)	Sep. 30, 2019 GBP (£)	Jun. 30, 2019 GBP (£)
Derivative [Line Items]
Gains (losses) on non-derivative net investment hedge		$ (3,000,000)		$ 26,000,000
Gains (losses) from cash flow hedges recorded within other comprehensive income	$ (12,000,000)	8,000,000	$ (36,000,000)	33,000,000
Derivatives designated for hedge accounting
Derivative [Line Items]
Gain (loss) from net investment hedges recorded within other comprehensive income	(84,000,000)	(59,000,000)	(201,000,000)	8,000,000
Forward contracts to hedge Euro against British Pound cash flows \| Derivatives not Designated for Hedge Accounting
Derivative [Line Items]
Notional values of financial instruments	13,000,000	250,000,000	13,000,000	250,000,000							$ 29,000,000
Gain (loss) on financial instruments		3,000,000		(36,000,000)
Net Investment Hedging \| Derivatives designated for hedge accounting
Derivative [Line Items]
Derivatives used in net investment hedge, gains (losses) gross	(45,000,000)	(20,000,000)	(108,000,000)	(11,000,000)
Net Investment Hedging \| November 2018 cross currency swaps \| Derivatives designated for hedge accounting
Derivative [Line Items]
Notional values of financial instruments						$ 999,000,000		$ 500,000,000					$ 1,500,000,000				£ 932
Proceeds from termination of derivative instruments				84,000,000
Gain (loss) on financial instruments				34,000,000
Cash Flow Hedging \| Derivatives designated for hedge accounting
Derivative [Line Items]
Gains (losses) from cash flow hedges recorded within other comprehensive income	(14,000,000)	$ 5,000,000	(42,000,000)	$ 40,000,000
Cash Flow Hedging \| Cross currency swap \| Derivatives designated for hedge accounting
Derivative [Line Items]
Notional values of financial instruments	$ 2,600,000,000		$ 2,600,000,000								$ 2,900,000,000
Cash Flow Hedging \| Forward starting interest rate swaps \| Derivatives designated for hedge accounting
Derivative [Line Items]
Notional values of financial instruments									$ 500,000,000	€ 600,000,000
Euro Denominated Notes \| Term Loan
Derivative [Line Items]
Long-term debt outstanding \| €														€ 1,700,000,000
Euro Denominated Notes \| Term Loan \| Derivatives not Designated for Hedge Accounting
Derivative [Line Items]
Long-term debt outstanding \| €														€ 250,000,000
Euro Denominated Notes \| Term Loan \| Net Investment Hedging
Derivative [Line Items]
Long-term debt outstanding \| €					€ 1,700,000,000							€ 1,700,000,000
British Pound Sterling Denominated Notes \| Term Loan
Derivative [Line Items]
Long-term debt outstanding \| £							£ 450								£ 450	£ 450
2025 Notes \| Term Loan
Derivative [Line Items]
Debt instrument term			5 years