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Stockholders' Equity (Deficit) - Schedule of Other Comprehensive Income (Loss), Net of Tax (Details) € in Millions, £ in Millions, $ in Millions | 3 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2021 USD ($) | Jun. 30, 2020 USD ($) | Jun. 30, 2021 EUR (€) | Mar. 31, 2021 EUR (€) | Jun. 30, 2020 EUR (€) | Sep. 30, 2019 GBP (£)
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | $ 12 | $ 27 |  |  |  |
Reclassified to income statement, net of income tax expense | 14 | 2 |  |  |  |
Other comprehensive income (loss), net of tax | 26 | 29 |  |  |  |
Foreign currency translation adjustments, tax | 0 | 0 |  |  |  |
Reclassified to income statement, tax | 0 | 0 |  |  |  |
Unrealized gains (loss) on cash flow hedges arising during period, tax | 0 | 0 |  |  |  |
Net actuarial loss and prior service cost arising during the period, tax | 0 | 0 |  |  |  |
Amortization of actuarial (gain) loss and prior service costs, tax | 0 | 0 |  |  |  |
Foreign currency translation adjustments and other, tax | 0 | 0 |  |  |  |
Net actuarial gain (losses) attributable to redeemable noncontrolling interest | 0 | 3 |  |  |  |
Foreign Currency Translation Adjustments, Net of Tax |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 34 | 96 |  |  |  |
Reclassified to income statement, net of income tax expense | 17 | 0 |  |  |  |
Other comprehensive income (loss), net of tax | 51 | 96 |  |  |  |
Translation gain (loss) attributable to redeemable noncontrolling interest | 9 | 58 |  |  |  |
Unrealized Losses on Net Investment Hedges, Net of Tax |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | (27) | (63) |  |  |  |
Reclassified to income statement, net of income tax expense | 0 | 0 |  |  |  |
Other comprehensive income (loss), net of tax | (27) | (63) |  |  |  |
Unrealized gains (losses) on net investment hedges arising during period, tax | 6 | 22 |  |  |  |
Reclassified to income statement, tax | 0 | 0 |  |  |  |
Gain (loss) from net investment hedges recorded within other comprehensive income | (6) |  |  |  |  |
Unrealized Gains (Losses) on Cash Flow Hedges, Net of Tax |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 0 | (5) |  |  |  |
Reclassified to income statement, net of income tax expense | 0 | 0 |  |  |  |
Other comprehensive income (loss), net of tax | 0 | (5) |  |  |  |
Reclassified to income statement, tax | 0 | 0 |  |  |  |
Net actuarial loss and prior servicecost arising during the period, net of income tax benefit |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 5 | 0 |  |  |  |
Amortization of actuarial loss, prior service cost and transition obligation, net of income tax expense |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | (1) | 2 |  |  |  |
Foreign currency translation adjustments and other, net of income tax expense |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 0 | (1) |  |  |  |
Changes in retirement-related benefit plans |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Reclassified to income statement, net of income tax expense | (2) | 0 |  |  |  |
Other comprehensive income (loss), net of tax | 2 | 1 |  |  |  |
Reclassified to income statement, tax | 1 | 0 |  |  |  |
Euro Denominated Notes | Term Loan |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Long-term debt outstanding | € |  |  |  |  | € 1,700 |
British Pound Sterling Denominated Notes | Term Loan |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Long-term debt outstanding | £ |  |  |  |  |  | £ 450
Net Investment Hedging | Euro Denominated Notes | Term Loan |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Long-term debt outstanding | € |  |  | € 1,700 | € 1,700 |  |
Derivatives designated for hedge accounting |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Gain (loss) from net investment hedges recorded within other comprehensive income | (22) | (34) |  |  |  |
Derivatives designated for hedge accounting | Net Investment Hedging |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |
Derivatives used in net investment hedge, gains (losses) gross | $ (5) | $ (51) |  |  |  |

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