Other Financial Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Other Current Assets
Prepaid expenses	$ 63us-gaap_PrepaidExpenseCurrent	$ 45us-gaap_PrepaidExpenseCurrent
Other	83us-gaap_OtherAssetsCurrent	80us-gaap_OtherAssetsCurrent
Total other current assets	146	125
Selected Current Liabilities
Accounts payable	482us-gaap_AccountsPayableCurrent	464us-gaap_AccountsPayableCurrent
Capital expenditures	$ 26	$ 44

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Aggregate carrying amount, as of the balance sheet date, of current assets not separately disclosed in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer).

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Amount of asset related to consideration paid in advance for costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer.

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