Capitalization (Details)	Jul. 27, 2018 shares	Jan. 22, 2018 USD ($) employee $ / shares shares	Jun. 30, 2018 $ / shares shares	Dec. 31, 2017 $ / shares
Class of Stock [Line Items]
Proceeds from issuance of equity		$ 2,500,000,000
Par Value, in dollars per share | $ / shares		$ 100
Amount of private placement shares | shares		30,120,482
Common stock, par value (in dollars per share) | $ / shares		$ 0.10	$ 0.1	$ 0.1
Amount of private placement		$ 850,000,000
Liquidation preference value		$ 1,000
Conversion price (in dollars per share) | $ / shares		$ 27.42
Conversion threshold of Preferred Stock (in shares) | shares		323,200
Common stock share cap (in shares) | shares		58,964,222
RWG number of board members | employee		2
Other Paid-in Capital
Class of Stock [Line Items]
Amount of private placement		$ 847,000,000
Common Stock
Class of Stock [Line Items]
Amount of private placement		$ 3,000,000
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock shares issued | shares		1,616,000	1,616,000
Par Value, in dollars per share | $ / shares			$ 100
Amount of preferred stock investment		$ 1,620,000,000
Series A Convertible Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Amount of preferred stock investment		162,000,000
Series A Convertible Preferred Stock | Other Paid-in Capital
Class of Stock [Line Items]
Amount of preferred stock investment		$ 1,460,000,000
FirstEnergy
Class of Stock [Line Items]
RWG number of board members | employee		3
Subsequent Event | Preferred Stock
Class of Stock [Line Items]
Number of shares converted (in shares) | shares	224,714
Subsequent Event | Common Stock
Class of Stock [Line Items]
Number of shares issued (in shares) | shares	8,195,257