Employee Benefit Plans (Expected Future Benefit Payments To Be Paid) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	$ 94
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	100
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	107
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	113
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	121
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	709
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	13
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	12
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	12
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	12
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	12
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	$ 57