v3.26.1
Shareholder Report, Line Graph (Details) - USD ($)
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended 15 Months Ended 18 Months Ended 21 Months Ended 24 Months Ended 27 Months Ended 30 Months Ended 33 Months Ended 36 Months Ended 39 Months Ended 42 Months Ended 45 Months Ended 48 Months Ended 51 Months Ended 54 Months Ended 57 Months Ended 60 Months Ended 63 Months Ended 66 Months Ended 69 Months Ended 72 Months Ended 75 Months Ended 78 Months Ended 81 Months Ended 84 Months Ended 87 Months Ended 90 Months Ended 93 Months Ended 96 Months Ended 99 Months Ended 102 Months Ended 105 Months Ended 108 Months Ended 111 Months Ended 114 Months Ended 117 Months Ended 120 Months Ended
May 31, 2016
Aug. 31, 2016
Nov. 30, 2016
Feb. 28, 2017
May 31, 2017
Aug. 31, 2017
Nov. 30, 2017
Feb. 28, 2018
May 31, 2018
Aug. 31, 2018
Nov. 30, 2018
Feb. 28, 2019
May 31, 2019
Aug. 31, 2019
Nov. 30, 2019
Feb. 29, 2020
May 31, 2020
Aug. 31, 2020
Nov. 30, 2020
Feb. 28, 2021
May 31, 2021
Aug. 31, 2021
Nov. 30, 2021
Feb. 28, 2022
May 31, 2022
Aug. 31, 2022
Nov. 30, 2022
Feb. 28, 2023
May 31, 2023
Aug. 31, 2023
Nov. 30, 2023
Feb. 29, 2024
May 31, 2024
Aug. 31, 2024
Nov. 30, 2024
Feb. 28, 2025
May 31, 2025
Aug. 31, 2025
Nov. 30, 2025
Feb. 28, 2026
May 31, 2026
C000072749                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value $ 10,000 $ 10,328 $ 10,088 $ 10,403 $ 10,598 $ 10,787 $ 10,783 $ 10,829 $ 10,757 $ 10,773 $ 10,752 $ 11,165 $ 11,478 $ 11,966 $ 11,903 $ 12,070 $ 11,824 $ 12,537 $ 12,863 $ 12,977 $ 13,066 $ 13,207 $ 12,978 $ 12,700 $ 11,968 $ 11,587 $ 11,194 $ 11,178 $ 11,400 $ 11,635 $ 11,985 $ 12,387 $ 12,460 $ 12,862 $ 13,066 $ 13,144 $ 13,230 $ 13,457 $ 13,668 $ 13,892 $ 13,977
C000072750                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,320 10,065 10,381 10,572 10,764 10,739 10,776 10,706 10,704 10,685 11,077 11,378 11,863 11,791 11,937 11,697 12,382 12,705 12,797 12,875 13,014 12,769 12,487 11,760 11,378 10,985 10,962 11,172 11,394 11,729 12,113 12,176 12,560 12,763 12,817 12,892 13,104 13,301 13,509 13,582
C000169957                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 500,000 516,565 504,266 520,646 530,793 540,515 540,282 542,786 539,874 540,388 540,011 560,483 576,396 601,107 598,656 606,766 595,221 630,802 647,444 653,423 658,177 666,075 654,225 640,499 604,437 584,864 565,823 564,678 576,728 588,257 606,189 627,392 630,709 651,363 662,609 666,164 670,805 682,599 693,590 705,238 709,858
Bloomberg Global Aggregate Bond Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,319 9,687 9,798 10,077 10,339 10,320 10,386 10,250 10,198 10,029 10,328 10,567 10,990 10,868 11,145 11,158 11,599 11,778 11,628 11,657 11,659 11,391 11,009 10,117 9,606 9,475 9,512 9,664 9,597 9,669 9,807 9,738 10,259 10,118 10,100 10,423 10,615 10,682 10,931 10,763
Bloomberg Global Aggregate Bond Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,319 9,687 9,798 10,077 10,339 10,320 10,386 10,250 10,198 10,029 10,328 10,567 10,990 10,868 11,145 11,158 11,599 11,778 11,628 11,657 11,659 11,391 11,009 10,117 9,606 9,475 9,512 9,664 9,597 9,669 9,807 9,738 10,259 10,118 10,100 10,423 10,615 10,682 10,931 10,763
Bloomberg Global Aggregate Bond Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 500,000 515,962 484,362 489,877 503,838 516,930 516,003 519,312 512,516 509,920 501,440 516,378 528,353 549,519 543,399 557,268 557,915 579,938 588,921 581,392 582,835 582,948 569,534 550,462 505,836 480,282 473,766 475,610 483,181 479,834 483,457 490,361 486,916 512,936 505,898 504,982 521,166 530,737 534,085 546,536 538,137
Bloomberg Global Aggregate Bond USD Hedged Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,246 9,978 10,054 10,177 10,274 10,286 10,212 10,297 10,351 10,341 10,615 10,967 11,462 11,376 11,699 11,737 11,838 11,949 11,736 11,747 11,927 11,868 11,479 10,915 10,735 10,619 10,564 10,811 10,794 10,895 11,144 11,162 11,602 11,715 11,811 11,838 12,007 12,217 12,392 12,284
Bloomberg Global Aggregate Bond USD Hedged Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,246 9,978 10,054 10,177 10,274 10,286 10,212 10,297 10,351 10,341 10,615 10,967 11,462 11,376 11,699 11,737 11,838 11,949 11,736 11,747 11,927 11,868 11,479 10,915 10,735 10,619 10,564 10,811 10,794 10,895 11,144 11,162 11,602 11,715 11,811 11,838 12,007 12,217 12,392 12,284
Bloomberg Global Aggregate Bond USD Hedged Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value $ 500,000 $ 512,301 $ 498,895 $ 502,707 $ 508,835 $ 513,718 $ 514,299 $ 510,615 $ 514,849 $ 517,536 $ 517,066 $ 530,728 $ 548,333 $ 573,106 $ 568,798 $ 584,948 $ 586,825 $ 591,878 $ 597,473 $ 586,822 $ 587,346 $ 596,349 $ 593,377 $ 573,948 $ 545,731 $ 536,750 $ 530,934 $ 528,191 $ 540,547 $ 539,720 $ 544,754 $ 557,212 $ 558,079 $ 580,081 $ 585,748 $ 590,531 $ 591,893 $ 600,355 $ 610,833 $ 619,586 $ 614,219