Summary of Significant Accounting Policies Contractual Future Minimum Lease Receipt Table (Details) $ in Millions	Dec. 31, 2015 USD ($)
Accounting Policies [Abstract]
Operating Leases, Future Minimum Payments Receivable, Current	$ 496
Operating Leases, Future Minimum Payments Receivable, in Two Years	433
Operating Leases, Future Minimum Payments Receivable, in Three Years	396
Operating Leases, Future Minimum Payments Receivable, in Four Years	372
Operating Leases, Future Minimum Payments Receivable, in Five Years	325
Operating Leases, Future Minimum Payments Receivable, Thereafter	1,644
Operating Leases, Future Minimum Payments Receivable	$ 3,666

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- Definition

Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6454179&loc=d3e41551-112718

+ Details

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- Definition

Future rental payments receivable within one year of the balance sheet date under an operating lease.

+ References

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- Definition

Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

+ References

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Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

+ References

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Future rental payments receivable within the third year from the balance sheet date under an operating lease.

+ References

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Future rental payments receivable within the second year from the balance sheet date under an operating lease.

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- Definition

Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

+ References

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