Income Taxes (Schedule of Reconciliation of the Total Amount of Unrecognized Tax Benefit) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance		$ 1	$ 1
Gross increases - assumed liability of acquired entity	26		2
Reductions - tax positions in prior period	(8)
Lapse of statute of limitations	(1)
Settlements	(1)	(1)	(2)
Unrecognized Tax Benefits, Ending Balance	$ 16		$ 1