Other Financial Information (Noncash Opearting Working Capital Increase (Decrease)) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Other Financial Information [Abstract]
Decrease in accounts receivable	$ 125,283	$ 109,105
Decrease (increase) in inventories	5,918	(4,659)
Decrease in prepaid expenses	9,206	99,524
Decrease in other		5,564
Decrease in accounts payable and accrued liabilities	(136,500)	(337,302)	[1]
Increase in current income tax liabilities	38,674	40,975
Net (increase) decrease in noncash operating working capital	42,581	(86,793)
Cash income taxes paid, net of refunds	9,448	(4,367)
Interest paid, net of amounts capitalized	72,136	52,654
Asset retirement costs capitalized	797	8,693
Decrease in capital expenditure accrual	$ 43,370	$ 165,329

[1] 2016 balances included payments for deepwater rig contract exit of $261.8 million.