For the three months ended June 30, 2018, the Company incurred share-based compensation costs of $14 million (2017: $16 million) related to share-settled restricted stock units and cash-settled restricted stock units and recorded associated tax benefits of $3 million (2017: $3.5 million).

For the six months ended June 30, 2018, the Company incurred share-based compensation costs of $29 million (2017: $44 million) and recorded associated tax benefits of $4 million (2017: $17 million, including $7 million related to excess tax benefits associated with the vesting of restricted stock units).

During the six months ended June 30, 2018, the fair value of share-settled restricted stock units and cash-settled restricted stock units that vested was $47 million (2017: $124 million which included $44 million attributable to a grant made in 2014 of three year cliff vesting service-based awards). At June 30, 2018 there were $121 million of unrecognized compensation costs (2017: $115 million) which are expected to be recognized over the weighted average period of 2.8 years.

Share-settled Awards

The following table provides a summary of nonvested share settled restricted stock units for the six months ended June 30, 2018:



	Share Settled Performance Vesting Restricted Stock Units				Share Settled - Service Based Restricted Stock Units
	Number of Restricted Stock Units		Weighted Average Grant Date Fair Value⁽¹⁾		Number of Restricted Stock Units		Weighted Average Grant Date Fair Value⁽¹⁾

Nonvested restricted stock units - beginning of period	230		$	57.08	1,355		$	57.09
Granted	104		48.89		719		49.16
Vested	(87	)	54.71		(483	)	54.39
Forfeited	—		—		(47	)	56.71
Nonvested restricted stock units - end of period	247		$	54.49	1,544		$	54.17

(1) Fair value is based on the closing price of common shares on the grant date.

Cash-settled awards

The following table provides a summary of nonvested cash settled restricted stock units for the six months ended June 30, 2018:



	Cash Settled Performance Vesting Restricted Stock Units		Cash Settled Service-based Restricted Stock Units
	Number of Restricted Stock Units		Number of Restricted Stock Units

Nonvested restricted stock units - beginning of period	42		988
Granted	—		456
Vested	(12	)	(377	)
Forfeited	—		(47	)
Nonvested restricted stock units - end of period	30		1,020

At June 30, 2018, the liability for cash-settled restricted stock units, included in other liabilities in the Consolidated Balance Sheets, was $13 million (2017: $14 million).