Inventories Schedule of inventories (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 1,219	$ 909
Work in process	580	500
Finished goods	441	466
Total	2,240gild_InventoryNetAndInventoryNoncurrent	1,875gild_InventoryNetAndInventoryNoncurrent
Inventories	1,908us-gaap_InventoryNet	1,386us-gaap_InventoryNet
Other long-term assets	$ 332us-gaap_InventoryNoncurrent	$ 489us-gaap_InventoryNoncurrent

Inventory Net And Inventory Noncurrent

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Inventories not expected to be converted to cash, sold or exchanged within the normal operating cycle.

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

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Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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