Leases - Schedule of Financial Condition Information Related to Operating Leases (Detail) $ in Millions |
Jun. 30, 2019
USD ($)
|
|---|---|
| Leases [Abstract] | |
| Operating lease ROU assets | $ 646 |
| Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] | us-gaap:OtherAssets |
| Operating lease liability | $ 754 |
| Operating Lease, Liability, Statement of Financial Position [Extensible List] | us-gaap:OtherLiabilities |