Basis of Presentation Basis of Presentations (Details) $ in Millions	Jul. 23, 2015 USD ($)	Jul. 29, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Par Value			$ 18,017	$ 17,347
Subsequent Event [Member]
Business Acquisition [Line Items]
Par Value		$ 10,500
Subsequent Event [Member] | Catamaran [Member]
Business Acquisition [Line Items]
People Served	35,000,000
Business Acquisition, Percentage of Voting Interests to be Acquired	100.00%
Delayed Draw Term Loan [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Par Value		$ 1,500
Catamaran Outstanding Common Shares [Member] | Subsequent Event [Member] | Catamaran [Member]
Business Acquisition [Line Items]
Payments made to Acquire Businesses, Gross	$ 12,900