Other Financial Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2014	Dec. 31, 2013
Other Current Assets
Prepaid expenses	$ 66	$ 47
Other	87	79
Total other current assets	153	126
Selected Current Liabilities
Accounts payable	506	440
Capital expenditures	$ 13	$ 11

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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