Supplemental Cash Flow Information (Details 1) (USD $)
In Billions, except Per Share data, unless otherwise specified
1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Other investing activities with significant non-cash components    
Dividends that have been declared but not yet paid (in dollars per share) $ 1.025 $ 0.855
Increase of Current Liabilities due to dividend declared but not paid $ 0.6 $ 0.6