Derivative Instruments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Jul. 31, 2014
Derivative [Line Items]
Net derivative gains to be reclassified into earnings within the next 12 months	$ 42
Offset asset	56
Offset liability	56
Net derivative assets	30
Net derivative liabilities	$ 6
Foreign Exchange Contract | Designated as Hedging Instrument | Cash Flow Hedging
Derivative [Line Items]
Derivative contract duration	18 months
Interest Rate Swap | Designated as Hedging Instrument | Fair Value Hedging
Derivative [Line Items]
Derivative liability	$ 2,400	$ 2,400
Minimum | Foreign Exchange Contract | Designated as Hedging Instrument
Derivative [Line Items]
Derivative contract duration	1 month
Maximum | Foreign Exchange Contract | Designated as Hedging Instrument
Derivative [Line Items]
Derivative contract duration	1 year