Related Party Transactions (Cost Allocation Agreements with Affiliates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transactions [Abstract]
Related Party Transaction, Written Termination Notice Period	30 days
Allocated Lease Expense	$ 4	$ 4	$ 10
Allocated Sub-Lease Rental Income (less than for 2015)	1	1	4
Commissions and Fees Paid to PAD	$ 143	$ 177	$ 172