Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Reserves on receivables	$ 11	$ 14
Accumulated depreciation	$ 1,974	$ 1,936
Preferred stock - par value	$ 1	$ 1
Preferred stock - authorized shares	36,000,000	36,000,000
Preferred stock - outstanding shares	0	0
Common stock - par value	$ 0.1	$ 0.1
Common stock - authorized shares	200,000,000	200,000,000
Common stock - issued shares	145,853,000	145,667,000