New Accounting Pronouncements (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
New Accounting Pronouncement, Early Adoption [Line Items]
Reduction in operating expenses	$ (934)	[1]	$ (834)	[1]	$ (2,560)	[1]	$ (2,368)	[1]
Income tax expense (benefit)	29		(32)		86		(228)
Accounting Standards Update 2014-01 [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Reduction in operating expenses	21		21		64		64
Income tax expense (benefit)	$ 21		$ 21		$ 64		$ 64

[1] Expenses for the segments include fully apportioned corporate overhead expenses.