v3.7.0.1

Debt (Letter of Credit) (Details) - USD ($) $ in Millions | Mar. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Line of Credit Facility [Line Items] |  |  |
Letters of Credit Outstanding, Amount |  | $ 891 | $ 991
Revolving Credit Facility [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Letters of Credit Outstanding, Amount | [1] | 471 | 535
CDH [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Letters of Credit Outstanding, Amount |  | 237 | 250
Various Project Financing Facilities [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Letters of Credit Outstanding, Amount |  | $ 183 | $ 206
[1] | The Corporate Revolving Facility represents our primary revolving facility

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- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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Balance Type: | na
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- Details
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Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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