The exercise price of outstanding share options.

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- Definition

The amount of expense from share-based payment transactions with employees.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

The number of share options outstanding in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The maximum number of share options available to gran in a share-based payment arrangement.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

No definition.

+ References

No definition available.

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OTHER NOTES TO THE ACCOUNTS - Stock Options Outstanding (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) Options shares	Dec. 31, 2015 USD ($) Options shares	Dec. 31, 2017 GBP (£) Options shares
Share option activities
Number of share options outstanding in share-based payment arrangement at end of period \| Options		5,780,000	7,235,000	5,277,000
Maximum number of share options available to grant \| shares		5,807,000	6,402,000	5,854,000
Expense for share-based payments \| $	$ 31	$ 27	$ 30
Minimium
Share option activities
Exercise price of outstanding share options at ending of period				£ 5.35
Maximum
Share option activities
Exercise price of outstanding share options at ending of period				£ 10.92