Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Operating activities:
Net income	$ 386,630	$ 517,198
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	200,862	202,348
Gain on disposition of assets	(79,077)	(3,881)
Loss (gain) on foreign currency forward exchange contracts	2,977	(7,231)
Deferred tax provision	(1,101)	(15,623)
Accretion of discounts on marketable securities	3,626	(231)
Stock-based compensation expense	2,500	2,920
Deferred income, net	(7,517)	(32,490)
Deferred expenses, net	46,379	54,789
Other assets, noncurrent	2,310	(217)
Other liabilities, noncurrent	4,486	424
(Payments of) proceeds from settlement of foreign currency forward exchange contracts designated as accounting hedges	(2,977)	7,231
Other	526	(229)
Changes in operating assets and liabilities:
Accounts receivable	31,424	51,147
Prepaid expenses and other current assets	(16,188)	(24,137)
Accounts payable and accrued liabilities	(7,087)	(33,070)
Taxes payable	45,572	4,691
Net cash provided by operating activities	613,345	723,639
Investing activities:
Capital expenditures (including rig construction)	(384,693)	(578,841)
Proceeds from disposition of assets, net of disposal costs	136,618	4,205
Proceeds from sale and maturities of marketable securities	1,400,050	3,312,089
Purchases of marketable securities	(1,477,115)	(3,399,797)
Net cash used in investing activities	(325,140)	(662,344)
Financing activities:
Payment of dividends	(245,732)	(245,812)
Other	121
Net cash used in financing activities	(245,611)	(245,812)
Net change in cash and cash equivalents	42,594	(184,517)
Cash and cash equivalents, beginning of period	333,765	464,393
Cash and cash equivalents, end of period	$ 376,359	$ 279,876