| Debt  - Senior Notes (Details) - USD ($) | 6 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
| Dec. 31, 2019 | Oct. 31, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Jun. 30, 2018 | Nov. 30, 2014 | Oct. 31, 2014 | |
| Debt Instrument | |||||||
| Unamortized discount | $ 8,319,000 | $ 8,738,000 | |||||
| Treasury lock | Derivatives designated as hedging instruments | Cash flow hedge contracts - foreign currency | 2018 Rate lock agreements | Senior notes | |||||||
| Debt Instrument | |||||||
| Derivative, notional amount | $ 500,000,000.0 | ||||||
| Treasury lock | Derivatives designated as hedging instruments | Cash flow hedge contracts - foreign currency | Portion of senior notes | Senior notes | |||||||
| Debt Instrument | |||||||
| Derivative, notional amount | $ 1,000,000,000.00 | ||||||
| Senior notes | |||||||
| Debt Instrument | |||||||
| Face amount | $ 1,200,000,000 | $ 2,500,000,000 | |||||
| Face amount, repaid | $ 250,000,000.0 | ||||||
| Unamortized discount | $ 6,700,000 | $ 4,000,000.0 | |||||
| Redemption price | 101.00% | ||||||
| Fair value disclosure | $ 3,560,000,000 | $ 3,700,000,000 | 
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- Definition Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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