Shareholders' Equity (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (2,374)
Other comprehensive income (loss) before reclassifications, net	19
Amounts reclassified from accumulated other comprehensive loss:
Amounts reclassified from accumulated other comprehensive loss	50
Tax benefit	(15)
Amounts reclassified from accumulated other comprehensive loss, net	35
Net current period other comprehensive (loss) income	54
Ending balance	(2,320)
Change in Fair Value of Investments [Member]
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1	[1]
Other comprehensive income (loss) before reclassifications, net	1	[1]
Amounts reclassified from accumulated other comprehensive loss:
Amounts reclassified from accumulated other comprehensive loss	0	[1]
Tax benefit	0	[1]
Amounts reclassified from accumulated other comprehensive loss, net	0	[1]
Net current period other comprehensive (loss) income	1	[1]
Ending balance	2	[1]
Change in Fair Value of Derivatives [Member]
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(22)	[1]
Other comprehensive income (loss) before reclassifications, net	0	[1]
Amounts reclassified from accumulated other comprehensive loss:
Amounts reclassified from accumulated other comprehensive loss	14	[1]
Tax benefit	(5)	[1]
Amounts reclassified from accumulated other comprehensive loss, net	9	[1]
Net current period other comprehensive (loss) income	9	[1]
Ending balance	(13)	[1]
Foreign Currency Translation Adjustments [Member]
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	169
Other comprehensive income (loss) before reclassifications, net	18
Amounts reclassified from accumulated other comprehensive loss:
Amounts reclassified from accumulated other comprehensive loss	0
Tax benefit	0
Amounts reclassified from accumulated other comprehensive loss, net	0
Net current period other comprehensive (loss) income	18
Ending balance	187
Post-Retirement Benefit Obligation [Member]
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,522)	[2]
Other comprehensive income (loss) before reclassifications, net	0	[2]
Amounts reclassified from accumulated other comprehensive loss:
Amounts reclassified from accumulated other comprehensive loss	36	[2]
Tax benefit	(10)	[2]
Amounts reclassified from accumulated other comprehensive loss, net	26	[2]
Net current period other comprehensive (loss) income	26	[2]
Ending balance	$ (2,496)	[2]

[1] Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Other income

[2] Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Compensation and benefits