Derivative Instruments and Hedging Activities - Part 2 (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Assets
Derivative Assets, Gross	$ 212	$ 240
Liabilities
Derivative Liabilities, Gross	502	371
Subject to netting arrangement [Member]
Assets
Derivative Assets, Gross	69	91
Derivative Assets Not Offset Under Netting Arrangements	(18)	(9)
Derivative Assets Not Offset By Collateral	0	(3)
Derivative Assets, Net	51	79
Liabilities
Derivative Liabilities, Gross	484	314
Derivative Liabilities Not Offset Under Netting Arrangements	(18)	(9)
Derivative Liabilities Not Offset By Collateral	(19)	(6)
Derivative Liabilities, Net	447	299
Current [Member]
Assets
Derivative Assets, Gross	73	32
Liabilities
Derivative Liabilities, Gross	185	157
Noncurrent [Member]
Assets
Derivative Assets, Gross	139	208
Liabilities
Derivative Liabilities, Gross	317	214
Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	58	113
Liabilities
Derivative Liabilities, Gross	471	351
Not Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	154	127
Liabilities
Derivative Liabilities, Gross	31	20
No longer carried at fair value [Member]
Assets
Derivative Assets, Gross	163	169
Liabilities
Derivative Liabilities, Gross	185	190
Interest rate derivatives [Member]
Assets
Derivative Assets, Gross	22	98
Liabilities
Derivative Liabilities, Gross	409	322
Interest rate derivatives [Member] | Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	20	96
Liabilities
Derivative Liabilities, Gross	406	318
Interest rate derivatives [Member] | Not Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	2	2
Liabilities
Derivative Liabilities, Gross	3	4
Cross currency derivatives [Member]
Assets
Derivative Assets, Gross	0	5
Liabilities
Derivative Liabilities, Gross	11	11
Cross currency derivatives [Member] | Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	0	5
Liabilities
Derivative Liabilities, Gross	11	11
Cross currency derivatives [Member] | Not Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	0	0
Liabilities
Derivative Liabilities, Gross	0	0
Foreign currency derivatives [Member]
Assets
Derivative Assets, Gross	126	113
Liabilities
Derivative Liabilities, Gross	39	21
Foreign currency derivatives [Member] | Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	5	4
Liabilities
Derivative Liabilities, Gross	29	15
Foreign currency derivatives [Member] | Not Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	121	109
Liabilities
Derivative Liabilities, Gross	10	6
Commodity derivatives [Member]
Assets
Derivative Assets, Gross	64	24
Liabilities
Derivative Liabilities, Gross	43	17
Commodity derivatives [Member] | Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	33	8
Liabilities
Derivative Liabilities, Gross	25	7
Commodity derivatives [Member] | Not Designated as Hedging Instruments [Member]
Assets
Derivative Assets, Gross	31	16
Liabilities
Derivative Liabilities, Gross	$ 18	$ 10