Commitments and Contingencies - Future Minimum Commitments Under Our corporate Headquarters Lease and Other Non-Cancelable Operating Leases (Details) $ in Millions	Dec. 31, 2016 USD ($)
Commitment And Contingencies [Line Items]
2017	$ 25
Thereafter	120
Property leases, Total	248
2017	(1)
2018	(1)
2019	(1)
Total minimum lease payments	(3)
2017	25
2018	25
2019	26
2020	26
2021	26
Thereafter	120
Total minimum lease payments	248
Corporate Headquarters Lease
Commitment And Contingencies [Line Items]
2017	9
2018	9
2019	9
2020	9
2021	10
Thereafter	87
Property leases, Total	133
Other Operating Leases
Commitment And Contingencies [Line Items]
2017	17
2018	17
2019	18
2020	17
2021	16
Thereafter	33
Property leases, Total	$ 118