New Accounting Pronouncements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
New Accounting Pronouncement, Early Adoption [Line Items]
Reduction in operating expenses	$ (876)	[1]	$ (766)	[1]	$ (1,626)	[1]	$ (1,534)	[1]
Income tax expense (benefit)	206		(71)		57		(196)
Accounting Standards Update 2014-01 [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Reduction in operating expenses	21		21		42		42
Income tax expense (benefit)	$ 21		$ 21		$ 42		$ 42

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