Retirement And Employee Benefit Plans (Amounts Recognized In Other Comprehensive Income) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Current period net gain (loss)	[1]	$ (3)	$ (15)	$ 11
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current period net gain (loss)		$ (4)
Amortization of prior service cost
Amortization of net loss		$ 2
Settlements
Total		$ (2)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current period net gain (loss)		$ 1
Amortization of prior service cost
Amortization of net loss
Settlements
Total		$ 1

[1] Net of $0, ($10), and $8 million in taxes for the years ended December 31, 2015, 2014 and 2013, respectively.