Stockholders' Equity (Narrative) (Details) $ / shares in Units, € / shares in Thousands, $ in Millions	1 Months Ended	9 Months Ended
	Sep. 30, 2020 segment € / shares	Sep. 30, 2020 € / shares	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Line Items]
Preferred stock, authorized (in shares)			10,000,000	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 1.00	$ 1
Telco LLC
Class of Stock [Line Items]
Nonconvertible cumulative preferred interests issued | $			$ 2,000
Initial preferred distribution percentage	4.25%
Distribution reset period	7 years
Period post issuance date that preferred interests can be called at issue price	7 years
Option to require redemption, certain contingent events, failure of Telco LLC to pay preferred distributions, minimum number of periods | segment	2
Preferred Stock - Series A
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			48,000	48,000
Preferred stock, issued (in shares)			48,000	48,000
Preferred stock, liquidation preference per share (in dollars/Euros per share) | $ / shares			$ 25,000
Preferred stock, dividend rate		5.00%
Preferred Stock - Series B
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			20,000	0
Preferred stock, issued (in shares)			20,000	0
Preferred stock, liquidation preference per share (in dollars/Euros per share) | € / shares	€ 100	€ 100
Preferred stock, dividend rate		2.875%
Preferred Stock - Series C
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			70,000	0
Preferred stock, issued (in shares)			70,000	0
Preferred stock, liquidation preference per share (in dollars/Euros per share) | $ / shares			$ 25,000
Preferred stock, dividend rate		4.75%