Long-Term Debt and Revolving Promissory Note - Schedule of Debt Maturity (Details) $ in Millions	Dec. 31, 2018 USD ($)
Maturities of long-term debt (excluding unamortized premiums and discounts and unamortized debt issuance costs and other and excluding note payable-affiliate)
2019	$ 11
2020	5
2021	951
2022	0
2023	1
2024 and thereafter	5,109
Total long-term debt	$ 6,077

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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