Retirement And Employee Benefit Plans (Fair Value Measurement Of Pension Plan Assets) (Details) - Pension Benefits [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 108	$ 108
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	59	58
Equity Securities [Member] | Significant Observable Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	49	50
Equity Securities [Member] | Large Cap Growth Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9	8
Equity Securities [Member] | Large Cap Growth Equity [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9	8
Equity Securities [Member] | Large Cap Value Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9	9
Equity Securities [Member] | Large Cap Value Equity [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9	9
Equity Securities [Member] | Large Cap Core Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	19
Equity Securities [Member] | Large Cap Core Equity [Member] | Significant Observable Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	19
Equity Securities [Member] | Small Cap Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3	3
Equity Securities [Member] | Small Cap Equity [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3	3
Equity Securities [Member] | Non-U.S. Developed Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31	29
Equity Securities [Member] | Non-U.S. Developed Equity [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31	29
Equity Securities [Member] | Emerging Market Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	5
Equity Securities [Member] | Emerging Market Equity [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	5
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31	31
Fixed Income [Member] | Significant Observable Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31	31
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	4
Cash and Cash Equivalents [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2	$ 4