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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Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Related Party Transactions - Narrative (Details) - 6% Senior Notes due September 1, 2023 - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018	Mar. 09, 2018	Mar. 08, 2018
Related Party Transaction [Line Items]
Stated interest rate	6.00%
Senior notes
Related Party Transaction [Line Items]
Stated interest rate	6.00%	6.00%	6.00%	6.00%
Outstanding amount		$ 350