Related Party Transactions - Schedule of Other Related Party Balances (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Accounts receivable	$ 29.0	$ 29.0
Prepaid expenses	15.0	15.0
Other assets	2.0	3.0
Accounts payable	10.0	9.0
Deferred revenue	0.0	3.0
Accrued liabilities	19.0	16.0
Debt payable	2,692.0	2,091.0
Accrued interest, related parties	18.0	14.0
Other accrued liabilities, related parties	1.0	2.0
Unamortized debt issuance expense	2.0	3.0
Affiliated Entity
Related Party Transaction [Line Items]
Unamortized debt issuance expense	$ 2.0	$ 3.0

Accrued interest related parties current.

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Carrying value as of the balance sheet date of obligations incurred and payable to related parties, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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The carrying amount of consideration received or receivable from related parties as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income.

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Other accrued liabilities related parties current.

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Amount for accounts payable to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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The amount for notes payable (written promise to pay), payable to related parties, which are due after one year (or one business cycle).

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Amount of noncurrent assets classified as other.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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