Debt Leases and Banking Arrangements (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Line of Credit Facility [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,400
$ 900 million unsecured credit facility
Line of Credit Facility [Abstract]
Letters of Credit Outstanding, Amount	0
$ 2 billion WPZ unsecured credit facility (terminated)
Line of Credit Facility [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	2,000
Bilateral bank agreements for letters of credit
Line of Credit Facility [Abstract]
Letters of Credit Outstanding, Amount	27
New $2.4 billion WPZ unsecured credit facility
Line of Credit Facility [Abstract]
Letters of Credit Outstanding, Amount	0
Line of Credit Facility, Amount Outstanding	375
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,300