Share-Based Compensation (Details 2) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Restricted Stock Awards and Restricted Stock Units RSU [Member] | Minimum [Member]
Equity stock-based compensation
Vesting terms	3 years
Restricted Stock Awards and Restricted Stock Units RSU [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 (RSUs) [Member]
Restricted shares and unit activity
Non-vested at the beginning of the period (in shares)	469
Granted (in shares)	158
Vested (in shares)	(161)
Cancelled (in shares)	(23)
Non-vested at the end of the period (in shares)	443
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)	$ 61.29
Vested (in dollars per share)	$ 48.48
Cancelled (in dollars per share)	$ 54.74
Non-vested at the end of the period (in dollars per share)	$ 59.09
Unrecognized compensation cost	$ 13
Weighted-average period for amortization of unrecognized compensation cost	2 years