Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Net income	$ 456,071	$ 564,816
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	291,107	300,069
Gain on disposition of assets	(2,789)	(79,285)
Loss on foreign currency forward exchange contracts	2,246	5,692
Deferred tax provision	43,414	(6,089)
Accretion of discounts on marketable securities	(584)	4,461
Stock-based compensation expense	2,627	3,248
Deferred income, net	(45,600)	(19,020)
Deferred expenses, net	20,441	58,391
Long-term employee remuneration programs	6,617	4,572
Other assets, noncurrent	(4,487)	2,697
Other liabilities, noncurrent	(51)	2,457
Proceeds from (payments of) settlement of foreign currency forward exchange contracts designated as accounting hedges	(2,246)	(5,692)
Other	1,418	800
Changes in operating assets and liabilities:
Accounts receivable	74,965	108,159
Prepaid expenses and other current assets	(327)	(9,350)
Accounts payable and accrued liabilities	25,583	4,961
Taxes payable	(10,505)	68,711
Net cash provided by operating activities	857,900	1,009,598
Investing activities:
Capital expenditures (including rig construction)	(740,460)	(514,672)
Proceeds from disposition of assets, net of disposal costs	3,357	136,937
Proceeds from sale and maturities of marketable securities	3,225,062	2,075,106
Purchases of marketable securities	(2,874,689)	(2,352,635)
Net cash used in investing activities	(386,730)	(655,264)
Financing activities:
Payment of dividends	(367,945)	(367,984)
Credit facility arrangement fees	(1)	(3,646)
Other	138	130
Net cash used in financing activities	(367,808)	(371,500)
Net change in cash and cash equivalents	103,362	(17,166)
Cash and cash equivalents, beginning of period	335,432	333,765
Cash and cash equivalents, end of period	$ 438,794	$ 316,599