CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Capitalization
Common stock, shares authorized (in shares)	1,000,000,000		1,000,000,000
Common stock, par value (in dollars per share)	$ 2.50		$ 2.50
Common stock, shares outstanding (in shares)	507,535,523	506,959,395	505,733,267