Common Stock (Details 1) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Sep. 30, 2011 Year	Jun. 30, 2011 Year	Mar. 31, 2011 Year
Stock options status and activity
Shares Under Option Outstanding Beginning Balance	3,032,224	3,135,520	3,129,241
Weighted Avg. Exercise Prices, Outstanding, Beginning Balance	$ 16.71	$ 16.53	$ 14.43
Weighted Avg. Remaining Life In Years, Beginning Balance	4.2	4.4	4.3
Aggregate Intrinsic Value, Outstanding, Beginning Balance	$ 76	$ 80	$ 68
Shares Under Option, Granted	1,649	2,711	201,133
Weighted Avg. Exercise Prices, Granted	$ 44.02	$ 43.51	$ 45.42
Shares Under Option Expired			(56,046)
Weighted Avg Exercise Price Expired			$ 3.66
Shares Under Option, Forfeited	(450)	(23,841)	(13,184)
Weighted Avg. Exercise Prices, Forfeited	$ 4.03	$ 14.26	$ 9.36
Shares Under Option, Exercised	(115,249)	(82,166)	(125,624)
Weighted Avg. Exercise Prices, Exercised	$ 8.94	$ 11.50	$ 17.10
Aggregate Intrinsic Value, Exercised	3	3	3
Shares Under Option Outstanding Ending Balance	2,918,174	3,032,224	3,135,520
Weighted Avg. Exercise Prices, Outstanding, Ending Balance	$ 17.03	$ 16.71	$ 16.53
Weighted Avg. Remaining Life In Years, Ending Balance	4.0	4.2	4.4
Aggregate Intrinsic Value, Outstanding, Ending Balance	$ 54	$ 76	$ 80