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Summary of Significant Accounting Policies (Details) - Accounting Standards Update 2016-02 $ in Millions | Jan. 01, 2019 USD ($)
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Operating Lease, Right-of-use Assets |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
Effect of new accounting principle | $ 11
Operating Lease, Right-of-use Assets | Properties |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
Effect of new accounting principle | 16
Operating Lease Liability | Properties |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
Effect of new accounting principle | 16
Finance Lease, Right-of Use Assets | Properties |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
Effect of new accounting principle | 38
Total Properties, Net |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
Effect of new accounting principle | $ (38)

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