Financial Instruments And Risk Management Financial Instruments And Risk Management (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Maximum length of time hedged in balance sheet hedge	30 days
Asset Derivatives	$ 4us-gaap_DerivativeAssets	$ 3us-gaap_DerivativeAssets
Liability Derivatives	13us-gaap_DerivativeLiabilities	7us-gaap_DerivativeLiabilities
Maximum length of time hedged in cash flow hedge	33 months
Balance sheet hedges - fair value	(41)	(47)
Balance sheet position - remeasurement	48	47
Net	7	0
Balance Sheet Hedge [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	1,470
Balance Sheet Hedge [Member] \| Australia, Dollars
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	375
Balance Sheet Hedge [Member] \| United States of America, Dollars
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	958
Balance Sheet Hedge [Member] \| United Kingdom, Pounds
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	86
Balance Sheet Hedge [Member] \| Sweden, Kronor
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	11
Balance Sheet Hedge [Member] \| Norway, Krone
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	2
Balance Sheet Hedge [Member] \| Canada, Dollars
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	25
Balance Sheet Hedge [Member] \| Saudi Arabia, Riyals
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	8
Balance Sheet Hedge [Member] \| India, Rupees
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Derivative, Notional Amount	5
Cash Flow Hedging [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Cash flow hedge	19
Other Current Assets [Member] \| Balance Sheet Hedge [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Asset Derivatives	4	3
Other Current Assets [Member] \| Cash Flow Hedging [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Asset Derivatives	0	0
Other Current Liabilities [Member] \| Balance Sheet Hedge [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Liability Derivatives	12	7
Other Current Liabilities [Member] \| Cash Flow Hedging [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Liability Derivatives	$ 1	$ 0

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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Maximum Length of Time Hedged in Balance Sheet Hedge

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount of unrealized gain (loss) included in earnings related to the fair value of the hedged item in an interest rate fair value hedge, offset by the gain (loss) on the hedging instrument to the extent that the fair value hedge is determined to be effective.

+ References

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The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

+ References

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Fair value as of the balance sheet date of interest rate derivative assets, net of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet.

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Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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