Share-Based Compensation (Details 2) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Restricted Stock Awards And Restricted Stock Units R S U [Member] | Minimum [Member]
Equity stock-based compensation
Vesting terms	3 years
Restricted Stock Awards And Restricted Stock Units R S U [Member] | Maximum [Member]
Equity stock-based compensation
Vesting terms	5 years
Restricted Stock [Member]
Restricted shares and unit activity
Non-vested at the beginning of the period (in shares)	48
Vested (in shares)	(31)
Cancelled (in shares)	(1)
Non-vested at the end of the period (in shares)	16
Weighted-average fair value per share
Non-vested at the beginning of the period (in dollars per share)	$ 26.25
Vested (in dollars per share)	$ 25.35
Cancelled (in dollars per share)	$ 28.75
Non-vested at the end of the period (in dollars per share)	$ 27.94
Restricted Stock Units R S U [Member]
Restricted shares and unit activity
Non-vested at the beginning of the period (in shares)	469
Granted (in shares)	157
Vested (in shares)	(154)
Cancelled (in shares)	(16)
Non-vested at the end of the period (in shares)	456
Weighted-average fair value per share
Non-vested at the beginning of the period (in dollars per share)	$ 54.47
Granted (in dollars per share)	$ 61.02
Vested (in dollars per share)	$ 48.82
Cancelled (in dollars per share)	$ 55.87
Non-vested at the end of the period (in dollars per share)	$ 58.59
Unrecognized compensation cost	$ 15
Weighted-average period for amortization of unrecognized compensation cost	2 years 2 months 12 days