Stock Compensation Plans and Other Compensation Arrangements (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Option Activity
Shares under option - exercised	(1.4)
Shares under option - outstanding at period end	0.3	1.7
Stock Options, Vested and Expected to Vest at Period End
Total intrinsic value of stock options exercised	$ 94	$ 118	$ 97
Aggregate intrinsic value - outstanding at period end	$ 28	$ 101	$ 66

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Number of share options (or share units) exercised during the current period.

+ References

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-Number 210

-Section 04

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