Joint Ventures and Other Equity Method Affiliates - Equity Income from Affiliates (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Equity Income from Affiliates [Line Items]
Equity income from affiliates	$ 257		$ 404		$ 642
Other [Member]
Equity Income from Affiliates [Line Items]
Equity income from affiliates	65	[1]	52	[1]	21	[1]
AstraZeneca LP [Member]
Equity Income from Affiliates [Line Items]
Equity income from affiliates	$ 192	[2]	$ 352	[2]	$ 621	[2]

[1] Includes results from Sanofi Pasteur MSD.

[2] As noted below, as of July 1, 2014, the Company no longer records equity income from AZLP.