Related Party (Cost Allocation Agreements with Affiliates) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Related Party Transactions [Abstract]
Allocated Lease Expense	$ 4	$ 4	$ 4
Allocated Sub-Lease Rental Income	4	2	4
Commissions and Fees Paid to PAD	$ 186	$ 185	$ 409