Common Stock (Narrative) (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2014 USD ($)	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($)
Class of Stock [Line Items]
Common stock, shares authorized		500,000,000	500,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
4 percent Convertible Senior Notes
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance		0	3,800,000
Stated interest rate		4.00%	4.00%	4.00%
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Restricted stock units outstanding (in shares)		700,000
Share conversion ratio		1
Shares issued for RSUs		597,000
Shares paid for tax withholding		351,000
Compensation expense not yet recognized | $		$ 26
Compensation expense not yet recognized, period for recognition		1 year 7 months 18 days
Fair value of RSUs vested during the period | $		$ 84	$ 54	$ 53
Time-based Restricted Stock Units
Class of Stock [Line Items]
Vesting period		3 years
Vesting period, start duration from grant date		12 months
Employee stock option
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance		600,000	700,000
2010 Long Term Incentive Plan
Class of Stock [Line Items]
Number of shares available for grant		5,500,000
Convertible debt | 4 percent Convertible Senior Notes
Class of Stock [Line Items]
Stated interest rate		4.00%	4.00%	4.00%
National Pump
Class of Stock [Line Items]
Value of stock issued in connection with business acquisition | $	$ 15
National Pump | Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Vesting period	3 years
Expense recorded during period related to stock awards | $		$ 5	$ 4