Significant Accounting Policies Capped Call (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Shares received upon settlement of capped call	0.6
Economic value of shares received upon settlement of capped call	$ 38
Maximum [Member]
option indexed to Company's own stock - strike price	$ 41.05
Option indexed to Issuer's own equity, cap price	$ 56.88
Minimum [Member]
option indexed to Company's own stock - strike price	$ 40.96
Option indexed to Issuer's own equity, cap price	$ 56.75