Leases Supplemental Operating Lease Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Leases [Abstract]
Operating cash flows for operating leases (for the nine months ended)	$ 50
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 42
Weighted-average remaining lease term in years for operating leases	6 years
Weighted-average discount rate for operating leases	3.50%