Issuances of Common Stock - At-the-Market (ATM) Programs (Details) $ in Billions	43 Months Ended
	Mar. 31, 2019 USD ($) shares
ATM Programs | Common stock distributions
At-the-Market (ATM) Programs
Share issuances, net of costs (in shares)	33,546,139
Proceeds from At-the-Market (ATM) program | $	$ 2.0
Current ATM Program
At-the-Market (ATM) Programs
Shares remaining for future issuance (in shares)	20,453,861
Current ATM Program | Common stock distributions | Maximum
At-the-Market (ATM) Programs
Shares authorized (in shares)	28,961,855