Summary of Significant Accounting Policies, Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2020
Pipeline Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Principal service lives	30 years
Pipeline Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Principal service lives	50 years
Offshore Drilling Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Principal service lives	15 years
Offshore Drilling Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Principal service lives	30 years
Hotel Properties and Other [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Principal service lives	3 years
Hotel Properties and Other [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Principal service lives	40 years