Income Taxes, Net Operating Losses (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
State
Operating Loss Carryforwards [Line Items]
State NOL carryforwards	$ 1,845
Deferred tax asset for State NOL carryforwards	$ 70
State | Minimum
Operating Loss Carryforwards [Line Items]
Expiration of NOL carryforwards	Dec. 31, 2017
State | Maximum
Operating Loss Carryforwards [Line Items]
Expiration of NOL carryforwards	Dec. 31, 2036
Federal
Operating Loss Carryforwards [Line Items]
Deferred tax asset for Federal NOL carryforward	$ 18
Federal | Minimum
Operating Loss Carryforwards [Line Items]
Expiration of NOL carryforwards	Dec. 31, 2018
Federal | Maximum
Operating Loss Carryforwards [Line Items]
Expiration of NOL carryforwards	Dec. 31, 2036