New accounting standards (Details 8) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement or change in accounting principle, effect of adoption, quantification	$ 112

Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements.

No definition available.

Name:	us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantification
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration