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Significant Transactions (Sky Transaction) (Details) £ / shares in Units, $ in Millions, £ in Billions |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Oct. 09, 2018 USD ($) | Oct. 09, 2018 GBP (£) | Dec. 31, 2019 USD ($) | Mar. 31, 2019 USD ($) | Oct. 09, 2018 £ / shares
Customer Relationships [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated weighted average useful life |  |  | 14 years |  |
Sky Limited [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Shares acquired, share price (in gbp per share) | £ / shares |  |  |  |  | £ 17.28
Percentage of voting interests acquired in period | 100.00% | 100.00% |  |  |
Cash consideration | $ 39,387 | £ 30.2 |  |  |
Deferred tax assets related to net operating losses |  |  |  | $ 1,200 |
Goodwill purchase accounting adjustment |  |  | $ 1,400 |  |
Incremental depreciation and amortization |  |  | $ 53 |  |
Property and equipment | 4,127 |  |  |  |
Sky Limited [Member] | Trade Names [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Indefinite-lived intangible assets acquired | 5,800 |  |  |  |
Sky Limited [Member] | Customer Relationships [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Finite-lived intangible assets acquired | $ 9,500 |  |  |  |
Sky Limited [Member] | Customer Relationships [Member] | Minimum [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated weighted average useful life | 6 years | 6 years |  |  |
Sky Limited [Member] | Customer Relationships [Member] | Maximum [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated weighted average useful life | 19 years | 19 years |  |  |
Sky Limited [Member] | Developed Technology and Software [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Finite-lived intangible assets acquired | $ 4,300 |  |  |  |
Sky Limited [Member] | Developed Technology and Software [Member] | Minimum [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated weighted average useful life | 4 years | 4 years |  |  |
Sky Limited [Member] | Developed Technology and Software [Member] | Maximum [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated weighted average useful life | 9 years | 9 years |  |  |
Customer Premise Equipment [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated useful lives |  |  | 6 years |  |
Customer Premise Equipment [Member] | Sky Limited [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Property and equipment | $ 1,400 |  |  |  |
Customer Premise Equipment [Member] | Sky Limited [Member] | Minimum [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated useful lives | 5 years | 5 years |  |  |
Customer Premise Equipment [Member] | Sky Limited [Member] | Maximum [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Estimated useful lives | 7 years | 7 years |  |  |

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