Segment Information (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation from segment income to net income
Total segment income	$ 641	$ (685)	$ 715	$ 782	$ 666	$ 736	$ 657	$ 654	$ 1,453	$ 2,713	$ 2,025
Other operating revenues	4,542	4,515	4,525	4,513	4,583	4,571	4,612	4,610	18,095	18,376	15,351
Depreciation and amortization									(4,541)	(4,780)	(4,026)
Impairment	0	(1,100)							(1,092)	0	0
Other unassigned operating expenses									(3,502)	(3,244)	(2,975)
Other income (expense), net									(1,229)	(1,463)	(1,077)
Income tax expense									(463)	(473)	(375)
NET (LOSS) INCOME	239	(1,045)	269	298	233	270	74	200	(239)	777	573
Operating segments (segments)
Reconciliation from segment income to net income
Total segment income									8,846	9,076	7,848
Other operating revenues									17,095	17,320	14,471
Unallocated amount to segment
Reconciliation from segment income to net income
Other operating revenues									1,000	1,056	880
Depreciation and amortization									(4,541)	(4,780)	(4,026)
Other unassigned operating expenses									(2,760)	(2,639)	(2,677)
Other income (expense), net									(1,229)	(1,463)	(1,077)
Income tax expense									$ (463)	$ (473)	$ (375)