Long-Term and Other Debt - Debt Issuance Costs (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Nov. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Gross financing costs	$ 42	$ 17	$ 16
Financing costs	34			$ 26
Debt issuance costs expensed	$ 8

Amount of amortization expense attributable to debt issuance costs.

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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

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