Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Stockholders’ equity-
Common stock, par value (in dollars per share)	$ 0.1	$ 0.1
Common stock, shares authorized	700,000,000	700,000,000
Common stock, shares outstanding	476,909,318	445,334,111
Customer
Receivables-
Allowance for uncollectible accounts	$ 50	$ 49
Other
Receivables-
Allowance for uncollectible accounts	1	$ 1
Affiliated Companies
Receivables-
Allowance for uncollectible accounts	$ 624
Series A Convertible Preferred Stock
Stockholders’ equity-
Par Value, in dollars per share	$ 100
Preferred stock, shares authorized	5,000,000
Preferred stock shares issued	1,616,000