Schedule I Condensed Balance Sheets (Paranthetical) - $ / shares shares in Millions	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	115	115
Common stock, shares issued	77	77
Common stock, shares outstanding	77	77
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	115	115
Common stock, shares issued	77	77
Common stock, shares outstanding	77	77