Stockholders' Equity (Schedule of Accumulated Other Comprehensive Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
AOCI [Roll Forward]
Accumulated other comprehensive loss, beginning balance	$ (5,441)	$ (8,646)	$ (8,750)
Other comprehensive income (loss) before reclassifications	(3,575)	2,656	(417)
Amounts reclassified from accumulated other comprehensive income (loss)	309	549	521
Accumulated other comprehensive loss, ending balance	(8,707)	(5,441)	(8,646)
Cumulative Translation Adjustment [Member]
AOCI [Roll Forward]
Accumulated other comprehensive loss, beginning balance	(140)	(167)	(244)
Other comprehensive income (loss) before reclassifications, CTA	(876)	27	77
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Accumulated other comprehensive loss, ending balance	(1,016)	(140)	(167)
Net Revaluation and Clearance of Cash Flow Hedges to Earnings [Member]
AOCI [Roll Forward]
Accumulated other comprehensive loss, beginning balance	(48)	3	41
Other comprehensive income (loss) before reclassifications, cash flow hedges	33	(36)	(1)
Amounts reclassified from accumulated other comprehensive income (loss), cash flow hedges	9	(15)	(37)
Accumulated other comprehensive loss, ending balance	(6)	(48)	3
Pension Benefit Plans, Net [Member]
AOCI [Roll Forward]
Accumulated other comprehensive loss, beginning balance	(5,749)	(8,686)	(8,276)
Other comprehensive income (loss) before reclassifications, pension and other benefit plans	(2,601)	2,197	(1,006)
Amounts reclassified from accumulated other comprehensive income (loss), pension and other benefit plans	401	740	596
Accumulated other comprehensive loss, ending balance	(7,949)	(5,749)	(8,686)
Other Long-Term Employee Benefit Plans [Member]
AOCI [Roll Forward]
Accumulated other comprehensive loss, beginning balance	494	202	(274)
Other comprehensive income (loss) before reclassifications, pension and other benefit plans	(131)	468	514
Amounts reclassified from accumulated other comprehensive income (loss), pension and other benefit plans	(101)	(176)	(38)
Accumulated other comprehensive loss, ending balance	262	494	202
Unrealized Gain (Loss) on Securities [Member]
AOCI [Roll Forward]
Accumulated other comprehensive loss, beginning balance	2	2	3
Other comprehensive income (loss) before reclassifications, securities	0	0	(1)
Amounts reclassified from accumulated other comprehensive income (loss), securities	0	0	0
Accumulated other comprehensive loss, ending balance	$ 2	$ 2	$ 2