Share-Based Compensation Share-Based Compensation - Performance Share Unit Breakout (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Performance Shares [Member]	Sep. 30, 2013 Performance Shares [Member]	Sep. 30, 2014 Performance Shares [Member]	Sep. 30, 2013 Performance Shares [Member]	Sep. 30, 2014 Performance Shares [Member] Year of 2012 [Member]	Sep. 30, 2013 Performance Shares [Member] Year of 2012 [Member]	Sep. 30, 2014 Performance Shares [Member] Payable 2015 [Member] Year of 2012 [Member]	Dec. 31, 2012 Performance Shares [Member] Payable 2015 [Member] Year of 2012 [Member]	Sep. 30, 2014 Performance Shares [Member] Payable 2016 [Member] Year of 2013 [Member]	Dec. 31, 2012 Performance Shares [Member] Payable 2016 [Member] Year of 2013 [Member]	Sep. 30, 2014 Performance Shares [Member] Payable 2017 [Member] Year of 2014 [Member]	Dec. 31, 2012 Performance Shares [Member] Payable 2017 [Member] Year of 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized											884,507		1,701,941		609,637
Allocated Share-based Compensation Expense	$ 25	$ 35	$ 81	$ 123	$ (13)	$ 25	$ 1	$ 41	$ 11	$ 2
Fair Value of Share Based Award											21	23	45	35	10	16
Share Based Award Liability, Current											$ 21		$ 42		$ 6