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Significant Transactions (Sky Offer) (Details) £ / shares in Units, £ in Billions, $ in Billions | Jul. 11, 2018 USD ($) | Jul. 11, 2018 GBP (£) £ / shares | Jun. 30, 2018 USD ($) | Apr. 25, 2018 USD ($) | Apr. 25, 2018 GBP (£)
--- | --- | --- | --- | --- | ---
Revolving Credit Facility [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Amount available under existing credit facility | $ |  |  | $ 7 |  |
Sky PLC [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Unsecured bridge credit agreement maximum borrowing capacity |  |  |  | $ 22 | £ 16
Unsecured term loan credit agreement maximum borrowing capacity |  |  |  | $ 10 | £ 7
Sky PLC [Member] | Subsequent Event [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Cash offer price per share (in gbp per share) | £ / shares |  | £ 14.75 |  |  |
Offer consideration | $ 34 | £ 26 |  |  |
Acquisition conditions, percentage of secured acceptance of voting rights |  | 50.00% |  |  |

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