XML 197 R160.htm IDEA: XBRL DOCUMENT v3.19.1
Authorised and issued share capital - Summary of Authorised and Issued Share Capital (Detail)
£ in Millions
 12 Months Ended
Dec. 31, 2018
GBP (£)
shares
Dec. 31, 2017
GBP (£)
shares
Dec. 31, 2016
GBP (£)
shares
Dec. 31, 2015
GBP (£)
shares
Disclosure of classes of share capital [line items]        
Issued and fully paid capital, Beginning balance [1] £ 133.3      
Issued and fully paid capital, Ending balance £ 133.3 £ 133.3 [1]    
Ordinary shares [member]        
Disclosure of classes of share capital [line items]        
Equity ordinary shares, authorised | shares 1,750,000,000 1,750,000,000 1,750,000,000 1,750,000,000
Nominal value of Authorised shares £ 175.0 £ 175.0 £ 175.0 £ 175.0
Number of shares issued and fully paid, Beginning balance | shares 1,332,511,552 1,331,880,730 1,329,366,024  
Exercise of share options | shares 166,675 630,822 2,514,706  
Number of shares issued and fully paid, Ending balance | shares 1,332,678,227 1,332,511,552 1,331,880,730  
Issued and fully paid capital, Beginning balance £ 133.3 £ 133.2 £ 132.9  
Exercise of share options   0.1 0.3  
Issued and fully paid capital, Ending balance £ 133.3 £ 133.3 £ 133.2  
[1] Prior year figures have been restated for the impact of the adoption of IFRS 15 Revenue from Contracts with Customers, as described in the accounting policies.