Schedule of Acquired Finite-Lived Intangile Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 11,863	$ 11,714
Finite-Lived Intangible Assets, Accumulated Amortization	1,222	388
Intangible Asset - Sofosbuvir [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	10,720	10,720
Finite-Lived Intangible Assets, Accumulated Amortization	757	58
Intangible Asset - Ranexa [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	688	688
Finite-Lived Intangible Assets, Accumulated Amortization	277	191
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	455	306
Finite-Lived Intangible Assets, Accumulated Amortization	$ 188	$ 139