Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Accumulated Translation Adjustment [Member]	Sep. 30, 2013 Accumulated Translation Adjustment [Member]	Sep. 30, 2014 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Sep. 30, 2014 Accumulated Defined Benefit Plans Adjustment [Member]	Sep. 30, 2013 Accumulated Defined Benefit Plans Adjustment [Member]	Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]	Sep. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member]	Dec. 31, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated other comprehensive loss
Balance at the beginning of the period			$ (583)	$ (475)	$ (489)	$ (335)	$ (40)	$ (17)	$ (53)	$ (121)	$ (2)	$ (1)	$ (1)
Losses on cash-flow hedges, net of income tax effect of $21 and $25 for the nine months ended September 30,2014 and 2013, respectively	(48)	(29)	(47)	(54)			(47)	(54)
Amount of losses on cash-flow hedges reclassified to earnings, net of income tax effect of $11 and $4 for the nine months ended September 30,2014 and 2013 respectively	11	18	24	10			24	10
Losses related to pension and other postretirement obligations reclassified to earnings, net of income tax effect	1	2	3	5					3	5
Unrealized gain on investment, net of income tax effect				1							1
Currency translation adjustment	(121)	6	(116)	(105)	(116)	(105)
Balance at end of the period	(719)	(618)	(719)	(618)	(605)	(440)	(63)	(61)	(50)	(116)	(1)	(1)	(1)
Income tax effect of accumulated other comprehensive gain (loss)
Losses on cash-flow hedges, income tax effect	(23)	(14)	(21)	(25)			(21)	(25)
Amount of losses on cash-flow hedges reclassified to earnings, income tax effect	$ (5)	$ (9)	$ (11)	$ (4)			$ (11)	$ (4)