Retirement And Employee Benefit Plans (Fair Value Measurement Of Pension Plan Assets) (Details) (Pension Benefits [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 108	$ 99
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	58	51
Equity Securities [Member] | Significant Observable Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50	48
Equity Securities [Member] | Large Cap Growth Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8	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	8	8
Equity Securities [Member] | Large Cap Value Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9	8
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	8
Equity Securities [Member] | Large Cap Core Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	16
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	19	16
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] | International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29	31
Equity Securities [Member] | International Equity [Member] | Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29	31
Equity Securities [Member] | Emerging Market Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	6
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
Equity Securities [Member] | Emerging Market Equity [Member] | Significant Observable Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		6
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31	26
Fixed Income [Member] | Significant Observable Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31	26
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	1
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	$ 4	$ 1