Financing Agreements - Long-term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2015		Dec. 31, 2014
Debt Instrument [Line Items]
Total	$ 1,605		$ 1,659
Less: current maturities	35		46
Total long-term debt	$ 1,570		$ 1,613
Senior Notes Due February 2019 [Member]
Debt Instrument [Line Items]
Interest Rate	6.50%		6.50%
Total	$ 0		$ 55
Senior Notes Due February 2021 [Member]
Debt Instrument [Line Items]
Interest Rate	6.75%		6.75%
Total	$ 350		$ 350
Senior Notes Due September 2021 [Member]
Debt Instrument [Line Items]
Interest Rate	5.375%		5.375%
Total	$ 450		$ 450
Senior Notes Due September 2023 [Member]
Debt Instrument [Line Items]
Interest Rate	6.00%		6.00%
Total	$ 300		$ 300
Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Interest Rate	5.50%		5.50%
Total	$ 425		$ 425
Other indebtedness [Member]
Debt Instrument [Line Items]
Total	$ 80	[1]	$ 79

[1] * Includes fair value adjustments related to an interest rate swap. See Note 11 for additional information.