Supplemental Equity and Comprehensive Income Information (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	$ (3,913)	$ (4,750)	$ (5,025)
Other comprehensive income (loss), before tax:
Amounts before reclassification	(3,321)	801	(62)
Amounts reclassified out	357	691	543
Total other comprehensive income (loss), before tax	(2,964)	1,492	481
Tax effect	563	(655)	(206)
Total other comprehensive income (loss), net of tax	(2,401)	837	275
Impact From Purchase Of Subsidiary Shares	25
Balance at End of Period	(6,289)	(3,913)	(4,750)
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(188)	230	114
Other comprehensive income (loss), before tax:
Amounts before reclassification	(856)	(462)	133
Amounts reclassified out	0	0	0
Total other comprehensive income (loss), before tax	(856)	(462)	133
Tax effect	(92)	44	(17)
Total other comprehensive income (loss), net of tax	(948)	(418)	116
Impact From Purchase Of Subsidiary Shares	41
Balance at End of Period	(1,095)	(188)	230
Defined Benefit Pension and Postretirement Plans Adjustment
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(3,715)	(4,955)	(5,155)
Other comprehensive income (loss), before tax:
Amounts before reclassification	(2,638)	1,361	(204)
Amounts reclassified out	360	569	615
Total other comprehensive income (loss), before tax	(2,278)	1,930	411
Tax effect	716	(690)	(211)
Total other comprehensive income (loss), net of tax	(1,562)	1,240	200
Impact From Purchase Of Subsidiary Shares	(16)
Balance at End of Period	(5,293)	(3,715)	(4,955)
Debt and Equity Securities, Unrealized Gain (Loss)
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(2)	(2)	(6)
Other comprehensive income (loss), before tax:
Amounts before reclassification	2	0	6
Amounts reclassified out	1	0	0
Total other comprehensive income (loss), before tax	3	0	6
Tax effect	(1)	0	(2)
Total other comprehensive income (loss), net of tax	2	0	4
Impact From Purchase Of Subsidiary Shares	0
Balance at End of Period	0	(2)	(2)
Cash Flow Hedging Instruments Unrealized Gain (Loss)
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(8)	(23)	22
Other comprehensive income (loss), before tax:
Amounts before reclassification	171	(98)	3
Amounts reclassified out	(4)	122	(72)
Total other comprehensive income (loss), before tax	167	24	(69)
Tax effect	(60)	(9)	24
Total other comprehensive income (loss), net of tax	107	15	(45)
Impact From Purchase Of Subsidiary Shares	0
Balance at End of Period	$ 99	$ (8)	$ (23)