Leases (Narrative) (Details) $ in Millions		6 Months Ended
	Dec. 22, 2016 USD ($) ft² state item	Jun. 30, 2019 USD ($) item
Capital Leased Assets [Line Items]
Operating lease right-of-use asset | $		$ 603
HCP, Inc. [Member]
Capital Leased Assets [Line Items]
Proceeds from sale-lease back | $	$ 159
Number of buildings in transaction | item	10
Area of real estate property | ft²	756,183
Number of states the buildings are located | state	5
Number of financing obligations remain outstanding | item		6
Number of medical office buildings divested | item		4
Medical Equipment [Member]
Capital Leased Assets [Line Items]
Operating lease right-of-use asset | $		$ 14