Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments (Details)

v2.4.1.9
Financial Instruments (Details) (Recurring, Level 2 market data, USD $)
In Billions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Recurring | Level 2 market data
   
Financial Instruments    
Fair value of senior notes $ 3.3us-gaap_NotesPayableFairValueDisclosure
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$ 2.5us-gaap_NotesPayableFairValueDisclosure
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