Employee Benefit Plans (The Estimated Portion of Balances Remaining in Accumulated Other Comprehensive Income (Loss) that are Expected to be Recognized as a Component of Net Periodic Benefit Cost) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Net loss	$ 38
Prior service cost (credit)	0
Qualified Plan
Net loss	30
Prior service cost (credit)	4
Non-Qualified Plan
Net loss	7
Prior service cost (credit)	(4)
Postretirement Benefit Plan
Net loss	1
Prior service cost (credit)	$ 0