Share-Based Compensation Plans Schedule of Performance-based plans (Details) (Performance Shares [Member], USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target PSAs granted during period	978	816	1,135
Weighted average fair value per share at date of grant	$ 96	$ 81	$ 58
Number of shares that would be issued based on current performance levels	978	1,201	2,197
Unamortized expense, based on current performance levels	$ 93	$ 61	$ 34

Represents the number of shares to be issued for performance-based stock award programs, based on the current performance levels.

No definition available.

+ Details

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- Definition

Represents unamortized expense of performance-based stock award plans, based on current performance levels.

+ References

No definition available.

+ Details

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

+ Details

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