v3.19.1

Income Taxes (Textuals) (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Intraperiod income tax [Line Items]
Number of States for NOL Carryforwards	26
Federal statutory tax expense (benefit) rate	21.00%	35.00%	35.00%
Income Tax Disclosure (Textuals) [Abstract]
Unrecognized Tax Benefits	$ 28,000,000	$ 38,000,000	$ 59,000,000	$ 58,000,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	16,000,000
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward	12,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2,000,000	4,000,000
Valuation allowance	1,000,000,000	1,168,000,000
Valuation Allowance, Deferred Tax Asset, Change in Amount	168,000,000	413,000,000	56,000,000
Deferred Tax Assets, Net of Valuation Allowance	869,000,000	836,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	(2,000,000)	$ (8,000,000)	$ 0
Expiration date 2024 through 2037 [Member]
Intraperiod income tax [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	6,400,000,000
Expiration date 2018 through 2037 [Member]
Income Tax Disclosure (Textuals) [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	3,300,000,000
Minimum [Member]
Income Tax Disclosure (Textuals) [Abstract]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	0
Maximum [Member]
Income Tax Disclosure (Textuals) [Abstract]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	1,000,000
Change in Valuation due to Merger [Member]
Income Tax Disclosure (Textuals) [Abstract]
Valuation Allowance, Deferred Tax Asset, Change in Amount	$ (58,000,000)

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